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Toxoplasma Gondii

Toxoplasma Gondii Book
Author : Louis M. Weiss,Kami Kim
Publisher : Elsevier
Release : 2011-04-28
ISBN : 9780080475011
Language : En, Es, Fr & De

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Book Description :

Toxoplasmosis is caused by a one-celled protozoan parasite known as Toxoplasma gondii. In the United States, it is estimated that approximately 30% of cats, the primary carriers, have been infected by T. gondii. Most humans contract toxoplasmosis by eating cyst-contaminated raw or undercooked meat, vegetables, or milk products or when they come into contact with the T. gondii eggs from cat feaces while cleaning a cat's litterbox, gardening, or playing in a sandbox. Approx 1 in 4 (more than 60 million) people in the USA are infected with the parasite, and in the UK between 0.5 and 1% of individuals become infected each year. By the age of 50, 40% of people test positive for the parasite. The predilection of this parasite is for the central nervous system (CNS) causing behavioral and personality alterations as well as fatal necrotizing encephalitis, and is especially dangerous for HIV infected patients. Though there have been tremendous strides in our understanding of the biology of Toxoplasma gondii in the last decade, there has been no systemic review of all of the information that has accumulated. Toxoplasma gondii provides the first comprehensive summary of literature on this organism by leading experts in the field who were responsible for organising the 7th International Congress on Toxoplasmosis in May 2003. It offeres systematic reviews of the biology of this pathogen as well as descriptions of the methods and resources used. Within the next year the T. gondii genome will be completed making this an indispensable research resource for biologists, physicians, parasitologists, and for all those contemplating experiments using T. gondii. * Serves as a model for understanding invasion of host cells by parasites, immune response, motility, differentiation, phylogenetics, evolution and organelle acquisition * Discusses the protocols related to genetic manipulation, cell biology and animal models while also providing reference material on available resources for working with this organism

Toxoplasma gondii

Toxoplasma gondii Book
Author : Uwe Gross
Publisher : Springer Science & Business Media
Release : 2012-12-06
ISBN : 3642510140
Language : En, Es, Fr & De

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Book Description :

For years, toxoplasmosis has been known as disease mostly affecting newborns. Since immunocompromised patients (AIDS) present a high risk of reactivation of chronic toxoplasmosis this parasitic disease has gained increasing interest. Besides presenting clinical and therapeutical concepts, this volume provides current knowledge about genetics and immunology of T. gondii and the interaction with its 'host'. Since in vivo and in vitro models of toxoplasmosis exist, and genetic manipulation has become possible, this protozoan parasite has recently been accepted as a model for understanding the pathogenesis and persistance of other intracellular parasites. The articles of the book compromise both reviewing current concepts and reporting on yet unpublished results of leading scientists in this field.

Toxoplasma Gondii Host Interactions A Story of Immune Attack and Parasite Counterattack

Toxoplasma Gondii Host Interactions  A Story of Immune Attack and Parasite Counterattack Book
Author : Jeroen P. J. Saeij,Eva Frickel,Kirk Jensen,Nicolas Blanchard
Publisher : Frontiers Media SA
Release : 2020-08-10
ISBN : 2889634027
Language : En, Es, Fr & De

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Book Description :

Toxoplasma gondii is an obligate intracellular parasite that can infect all warm-blooded animals, including an estimated ~30% of humans. It can cause severe disease in immune-suppressed individuals and in fetuses as well as blinding chorioretinitis in adults and children. Toxoplasma-innate immune system interactions determine early parasite control and activation of the adaptive immune system by the host and are therefore critical in determining host survival during the acute phase of infection. However, induction of an exaggerated inflammatory response can also lead to pathology. Only the chronic tissue cyst form of Toxoplasma is orally infectious. It is therefore critical for the parasite’s survival during the chronic phase to escape immune responses at this stage as well. Toxoplasma exists as genetically divergent strains mostly depending on geography, with the most strain diversity being found in South America. The key to Toxoplasma’s successful co-option of the host are proteins secreted from its rhoptry and dense granule secretory organelles. Rhoptry proteins (ROPs) are secreted into the host cell cytoplasm upon invasion while dense granule proteins (GRAs) are secreted once the parasite establishes itself in its parasitophorous vacuole (PV). GRAs can localize to the PV, the PV membrane, or are secreted beyond the PVM into the host cytoplasm. Many ROPs and GRAs are involved in modulating host cell signaling pathways and evasion of host immune responses and play important roles in Toxoplasma virulence. Polymorphisms in Toxoplasma’s ROPs and GRAs, likely determine how well these effectors bind to the divergent substrates in different host species, which can explain Toxoplasma strain differences in virulence in a particular host species. By studying Toxoplasma we have not only started to unravel how the parasite modulates immune responses to enhance its survival, replication, and transmission but we have also learned a lot about the immune system. Many unique mechanisms of immunity have indeed been defined using Toxoplasma and this parasite has aided our understanding of tissue-specific immune responses in the brain and intestine. This Research Topic will give a comprehensive overview of Toxoplasma-host immune response interactions. Most Toxoplasma virulence determinants to date have been established in murine systems and it is unclear how the parasite interacts with other intermediate hosts and humans. In addition, the interactions of Toxoplasma with some of the most relevant cell types during infection, including dendritic cells, neurons, intestinal epithelial cells or vascular endothelial cells, remain poorly understood.

Case Studies in Infectious Disease Toxoplasma Gondii

Case Studies in Infectious Disease  Toxoplasma Gondii Book
Author : Peter Lydyard,Michael Cole,John Holton,Will Irving,Nino Porakishvili,Pradhib Venkatesan,Kate Ward
Publisher : Garland Science
Release : 2009-12-01
ISBN : 1136985433
Language : En, Es, Fr & De

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Book Description :

Case Studies in Infectious Disease: Toxoplasma gondii presents the natural history of this infection from point of entry of the pathogen through pathogenesis, clinical presentation, diagnosis, and treatment. A set of core questions explores the nature, causation, host response, manifestations, and management of this infectious process. This case also includes summary bullet points, questions and answers, and references.

Toxoplasma Gondii Co opts Host Immune Signaling by Secretion of a Polymorphic Tyrosine Kinase ROP16

Toxoplasma Gondii Co opts Host Immune Signaling by Secretion of a Polymorphic Tyrosine Kinase  ROP16 Book
Author : N.A
Publisher : Stanford University
Release : 2010
ISBN :
Language : En, Es, Fr & De

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Book Description :

Toxoplasma gondii is an obligate, intracellular parasite of the Apicomplexan phylum that is able to infect nearly all warm-blooded vertebrates. This capability for survival in a variety of host niches is reflected in the diversification of Toxoplasma strains. Strains differ dramatically in their interaction with hosts, and a fruitful approach towards understanding the molecular underpinnings of disease has been to identify and characterize drivers of strain-specific differences in host response. Chapter 1 provides a general introduction to Toxoplasma gondii and its ability to modulate host immunity, with special attention given to what is known about the mechanisms behind strain-specific phenotypes and the role of one particular player, ROP16. Chapter 2 describes experiments demonstrating that Toxoplasma secretes a polymorphic tyrosine kinase, ROP16, that can directly phosphorylate host STAT6. These experiments made use of a targeted disruption of the ROP16 locus in Type I parasites to identify ROP16-dependent signaling pathways, and used biochemical approaches to dissect the mechanism by which ROP16 is able to induce rapid STAT6 activation. Chapter 3 describes work demonstrating that ROP16 activation of STAT6 directs murine macrophage polarization towards an alternatively activated (M2) phenotype. In Chapter 4, the avian host response to Toxoplasma is examined to determine whether strain-specific differences in host response might be inverted in non-mammalian hosts. We show that strain-specific transcriptional host response, as well as transcriptional host response modulated by ROP16, appears very similar in chickens as in mice and humans. This suggests that variance between mammalian and avian host species in general may not be the source of selective pressure for the success of these common strains, or of ROP16's variability. Chapter 5 concludes with a discussion of future directions for further characterization of ROP16's role in modulating host response. We show that ROP16 interacts with host chromatin and suggest that investigation of ROP16's function in the host nucleus might yield further molecular insights as to how Toxoplasma is able to co-opt host cells and influence the course of infection.

Congenital Toxoplasmosis In Vivo Impact of Toxoplasma Gondii Infection on Myogenesis and Neurogenesis

Congenital Toxoplasmosis  In Vivo Impact of Toxoplasma Gondii Infection on Myogenesis and Neurogenesis Book
Author : Alessandra F. Gomes
Publisher :
Release : 2017
ISBN :
Language : En, Es, Fr & De

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Book Description :

Congenital toxoplasmosis (TC) from Toxoplasma gondii positive mother to child transmission results in fetal death, abortion, or infantile neurologic and neurocognitive deficits as well as chorioretinitis. This study aims to analyze the morphological changes in brain and skeletal muscle cells of Swiss mouse embryos during experimental congenital toxoplasmosis. Swiss mice, before mating, were gavage inoculation infected with approximately 25 or 50 cysts of ME-49 strain T. gondii. Eighteen day postcoitus maternal and embryonic muscle and brain samples were collected and processed for histopathological analysis. The muscle tissue from embryos of infected mothers, in comparison with healthy muscle myofibers, exhibited discontinuous and shorter myofibrils, more interfibrillar space and immature cells with fewer stained and poorly defined striated profiles. These in vivo findings might be related to an adhesion protein decrease, observed in vitro, where myogenesis was completely affected during Toxoplasma infection. The neurogenesis was severely affected with irregularly arranged cells, reduced cell density, and a significant intercellular space increase. The brain tissue presented ischemia, cell death, necrosis, and thrombi, increasing according to the degree of the acute infection, which compromised the neurogenesis, thereby justifying brain size decrease in these embryos.

Toxoplasma Gondii in Meat for Human Consumption A Brief Review of the Most Described Strategies for Its Detection and Quantification

Toxoplasma Gondii in Meat for Human Consumption   A Brief Review of the Most Described Strategies for Its Detection and Quantification Book
Author : G.F. Dzib Paredes
Publisher :
Release : 2016
ISBN :
Language : En, Es, Fr & De

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Book Description :

Toxoplasmosis is a parasitic zoonotic disease widely distributed worldwide and is caused by the intracellular parasite Toxoplasma gondii. The definitive host of T. gondii is the domestic cat and the entire cat family, in which the sexual stages of the parasite develop. T. gondii can also infect a wide range of intermediate hosts, affecting most warm-blooded animals including humans. In humans, toxoplasmosis is usually asymptomatic in healthy individuals, but can develop lymphadenopathy and nonspecific symptomatology or even be fatal in infants with congenital toxoplasmosis and in immunocompromised patients. Transmission to humans is mainly through food, especially by eating undercooked meat or meat contaminated with tissue cysts. This has led to various public health organizations worldwide monitoring programs on T. gondii in animals intended for human consumption, especially in meat samples. One of the techniques employed in the laboratory is that based on the polymerase chain reaction and some of its variants, which have proven to be valuable tools for the detection of T. gondii in tissues for human consumption and many other types of biological samples. The development of different strategies for the molecular detection of T. gondii has led to the identification and quantification methodologies varying widely among laboratories. Therefore, this chapter reviews the main methods of extraction, purification, detection and quantification of T. gondii DNA in tissue samples from different species destined for human consumption.

Toxoplasma Gondii

Toxoplasma Gondii Book
Author : Gillian Woodison
Publisher :
Release : 1992
ISBN :
Language : En, Es, Fr & De

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Book Description :

Toxoplasma gondii

Toxoplasma gondii Book
Author : Christopher J. Tonkin
Publisher : Humana
Release : 2020-12-07
ISBN : 9781493998593
Language : En, Es, Fr & De

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Book Description :

This volume covers a diverse collection of protocols currently being used by the Toxoplasma research community, and also looks at innovative methods that are pushing the boundaries of possibilities. Chapters in this book discuss topics such as isolation and genotyping of Toxoplasma gondii strains; assessing rhoptry secretion in T. gondii; plate-based quantification of stimulated Toxoplasma egress; methods to study ocular toxoplasmosis; and metabolic analysis of Toxoplasma gondii tachyzoites. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Toxoplasma gondii: Methods and Protocols is a valuable resource for students or groups starting off in the field, as well as laboratories interested in implementing the latest techniques described in the book.

Chemotherapy and the Immune System

Chemotherapy and the Immune System Book
Author : L. H. Chappell,M. J. Doenhoff
Publisher : Cambridge University Press
Release : 1992
ISBN : 9780521448352
Language : En, Es, Fr & De

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Book Description :

This specially commissioned text covers a range of topics relating to chemotherapy and the immune system.

Toxoplasma Gondii and Schizophrenia A Relationship That Is Not Ruled Out

Toxoplasma Gondii and Schizophrenia  A Relationship That Is Not Ruled Out Book
Author : Antonio Sorlozano-Puerto
Publisher :
Release : 2016
ISBN :
Language : En, Es, Fr & De

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Book Description :

Over recent years, it has been proposed that some diseases of unknown origin, such as schizophrenia, may be caused by persistent chronic infections coupled with a genetic component and may be perpetuated by the immune system. This hypothesis is supported by epidemiological and biological evidence on the exposure of schizophrenics to infectious diseases during prenatal or postnatal periods, including Toxoplasma gondii, chlamydia, human herpes virus, human endogenous retroviruses, parvovirus B19, mumps, and flu viruses. This growing list of microbes will undoubtedly continue to increase in the future. Linking infection to schizophrenia is a complex challenge that requires further experimental and epidemiological research. T. gondii is the infectious agent that has most frequently been related to neuropsychiatric disorders, including schizophrenia, and it is considered to represent a highly useful model to analyze the influence of a microorganism on human behavior and the development of psychiatric disease. It may also help to detect patient subpopulations susceptible to treatment with specific antimicrobials by improving definition of the differential phenotype of the disease, and it offers the possibility of a preventive approach.

Latent Toxoplasma Gondii Infection Moderates the Association Between the C677T MTHFR Polymorphism and Cognitive Function in U S Adults

Latent Toxoplasma Gondii Infection Moderates the Association Between the C677T MTHFR Polymorphism and Cognitive Function in U S  Adults Book
Author : Andrew Nathan Berrett
Publisher :
Release : 2018
ISBN :
Language : En, Es, Fr & De

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Book Description :

Sufficient blood concentrations of folate and the products from its metabolism are necessary for several cellular functions. The C677T MTHFR polymorphism, present in over half of the U.S. population, reduces the efficiency of folate metabolism and has been linked to the onset of multiple psychiatric disorders and cognitive decline. The intracellular parasite Toxoplasma gondii can infect the human brain and is associated with increased prevalence of psychiatric disorders and cognitive decline. In vitro studies have found that Toxoplasma gondii may salvage unmetabolized folate from host cells. Since the C677T MTHFR polymorphism and infection by Toxoplasma gondii both affect folate metabolism or availability, I used data from the third National Health and Nutrition Examination Survey to test the hypothesis that laten toxoplasmosis and the C677T MTHFR polymorphism interact to predict worse cognitive functioning in U.S. adults. I found a statistically significant interaction effect between Toxoplasma gondii infection and the C677T MTHFR polymorphism in predicting performance on a test of reaction time. Subjects who were not infected with Toxoplasma gondii experienced declines in reaction time with the presence of one or two alleles for the C677T MTHFR polymorphism. However, this association was reversed for subjects who were seropositive for Toxoplasma gondii. No interaction effects were observed when predicting performance on a test of processing speed or a test of short term memory. In conclusion, these findings suggest that the co-occurrence of Toxoplasma gondii infection and the C677T MTHFR polymorphism may be associated with improved reaction time.

A Toxoplasma Gondii Model to Dissect Bradyzoite Recrudescence in Vitro

A Toxoplasma Gondii Model to Dissect Bradyzoite Recrudescence in Vitro Book
Author : Omar Alejandro Salas-Ortega
Publisher :
Release : 2019
ISBN :
Language : En, Es, Fr & De

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Book Description :

Toxoplasma gondii's chronic infection is critical for the parasite's persistence and unfortunately, this aspect of the parasite is vastly understudied. This is due to the challenges of culturing the cyst forming bradyzoites in vitro as they are often outcompeted by the rapidly growing tachyzoite form. To overcome this challenge, we generated an Me49 Type II strain containing a plasmid allowing the suppression of tachyzoite growth, selection for bradyzoites, and verification of conversion by stage specific fluorescent protein expression. Optimization of conversion using the cyclic-GMP protein kinase-inhibiting Compound 1 provided mature cysts in vitro to study bradyzoite biology. Addition of the calcium ionophore Ionomycin showed an inability by bradyzoites to egress from mature cysts and mechanical lysis showed an additional inability to re-invade new host cells. Treatment with conditions that mimic the gastrointestinal tract, acidic pH and pepsin protease (Acid/Pepsin) or the pancreatic protease Trypsin, activated bradyzoite invasion with the latter being the most effective activator. Chemical mutagenesis with ENU combined with an enrichment protocol involving mechanical lysis and outgrowth of mutants that no longer required protease treatment allowed the isolation of a parasite population, along with clones, that via whole genome sequencing would allow the identification of genes involved in this process. The ability to study bradyzoite biology in vitro provides a unique opportunity to observe and interrogate unexplored aspects of this crucial form of the parasite.

Investigations Into the Function of Elp3 in Toxoplasma Gondii

Investigations Into the Function of Elp3 in Toxoplasma Gondii Book
Author : Leah R. Padgett
Publisher :
Release : 2017
ISBN :
Language : En, Es, Fr & De

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Book Description :

The parasite Toxoplasma gondii causes life-threatening infection in immunocompromised individuals. Our lab has determined that Toxoplasma Elongator protein-3 (TgElp3) is required for parasite viability. While catalytic domains are conserved, TgElp3 is the only component of the six-subunit Elongator complex present in Toxoplasma; moreover, TgElp3 localizes to the outer mitochondria membrane (OMM). These unusual features suggest that TgElp3 may have unique roles in parasite biology that could be useful in drug targeting. The goals of this thesis were to determine the function of TgElp3 and how the protein traffics to the OMM. In other species, Elp3 mediates lysine acetylation of histones and alphatubulin, and its radical S-adenosyl methionine (rSAM) domain is important for the formation of tRNA modifications, which enhance translation efficiency and fidelity. Given its location, histones would not be an expected substrate, and we further determined that tubulin acetylation in Toxoplasma is mediated by a different enzyme, TgATAT. We found that overexpression of TgElp3 at the parasite's mitochondrion results in a significant replication defect, but overexpression of TgElp3 lacking the transmembrane domain (TMD) or with a mutant rSAM domain is tolerated. We identified one such modification, 5-methoxycarbonylmethyl-2thiouridine (mcm5S2U) that is likely mediated by TgElp3. These findings signify the importance of TgElp3's rSAM domain for protein function, and confirms TgElp3 activity at the OMM is essential for Toxoplasma viability as previously reported. To determine how TgElp3 traffics to the OMM, we performed a bioinformatics survey that discovered over 50 additional "tail-anchored" proteins present in Toxoplasma. Mutational analyses found that targeting of these TA proteins to specific parasite organelles was strongly influenced by the TMD sequence, including charge of the flanking C-terminal sequence.

Advances in Toxoplasma Research and Application 2013 Edition

Advances in Toxoplasma Research and Application  2013 Edition Book
Author : N.A
Publisher : ScholarlyEditions
Release : 2013-06-21
ISBN : 1481684302
Language : En, Es, Fr & De

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Book Description :

Advances in Toxoplasma Research and Application: 2013 Edition is a ScholarlyBrief™ that delivers timely, authoritative, comprehensive, and specialized information about ZZZAdditional Research in a concise format. The editors have built Advances in Toxoplasma Research and Application: 2013 Edition on the vast information databases of ScholarlyNews.™ You can expect the information about ZZZAdditional Research in this book to be deeper than what you can access anywhere else, as well as consistently reliable, authoritative, informed, and relevant. The content of Advances in Toxoplasma Research and Application: 2013 Edition has been produced by the world’s leading scientists, engineers, analysts, research institutions, and companies. All of the content is from peer-reviewed sources, and all of it is written, assembled, and edited by the editors at ScholarlyEditions™ and available exclusively from us. You now have a source you can cite with authority, confidence, and credibility. More information is available at http://www.ScholarlyEditions.com/.

Effects of Toxoplasma Gondii Infection on NK Cells and ILC1s

Effects of Toxoplasma Gondii Infection on NK Cells and ILC1s Book
Author : Eugene Park (Immunologist)
Publisher :
Release : 2020
ISBN :
Language : En, Es, Fr & De

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Book Description :

Natural killer cells and Type I innate lymphoid cells (ILCs) are subsets of ILCs. In C57BL/6 mice, they share expression of the surface markers NK1. 1 and NKp46, and can produce the cytokine interferon-gamma. These similarities led to the initial classification of natural killer cells and Type I ILCs together under the category of Group 1 ILCs. However, more recent studies found that natural killer cells and ILC1s develop from distinct progenitor cells and utilize transcription factor in distinct manners. Whereas ILC1s require Tbet for their development and are Eomes-independent, natural killer cells require Tbet only for terminal maturation and are Eomes-dependent. As such, these populations were reclassified as separate ILC subsets. In the context of Toxoplasma gondii infection, we identified a new population that blurs these strict delineations. Our data suggest that T. gondii induces the development of ILC1-like cells that primarily result from the downregulation of Eomes and the upregulation of Tbet. We further validated these findings with epigenomic profiling and single-cell RNA sequencing.

Identification of a Master Regulator of Differentiation in Toxoplasma Gondii

Identification of a Master Regulator of Differentiation in Toxoplasma Gondii Book
Author : Benjamin S. Waldman
Publisher :
Release : 2020
ISBN :
Language : En, Es, Fr & De

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Book Description :

Toxoplasma gondii is a parasite chronically infecting over a quarter of the world’s population. While Toxoplasma infection is asymptomatic in immunocompetent individuals, it can cause life-threatening disease in immunocompromised patients and the developing fetus. Acute symptoms of infection and dissemination of Toxoplasma throughout the body are due to the rapid proliferation of the tachyzoite stage of the parasite. While tachyzoites can eventually be cleared through adaptive immunity, a subset will differentiate into more slowly replicating bradyzoites. These bradyzoites form intracellular cysts in brain and muscle tissue that cannot be cleared by the immune system or by current therapeutics. Cysts thereby act as latent reservoirs of infection, and periodic reactivation of cysts results in lifelong risk of disease. While differentiation is readily induced in cell culture by diverse stressors, the molecular basis of this conversion is unknown. I therefore sought to determine the genetic requirements and regulation of bradyzoite differentiation in Toxoplasma. In this thesis, I describe the discovery and characterization of a master regulator of differentiation in Toxoplasma gondii. In my first chapter, I discuss application of CRISPR/Cas9-mediated forward genetic screening in Toxoplasma to identify a Myb-like transcription factor (BFD1; bradyzoite formation-deficient) as necessary for differentiation in cell culture and formation of brain cysts in mice. In my second chapter, I profile replicating and differentiating Toxoplasma in unprecedented detail through single-cell RNA-sequencing, and determine that parasites lacking BFD1 fail to initiate differentiation transcriptionally. In my third chapter, I demonstrate that BFD1 is post-transcriptionally regulated, and that conditional stabilization of BFD1 is sufficient to induce differentiation both phenotypically and transcriptionally in the absence of stress. BFD1 binds preferentially at transcriptional start sites, including those of many stage-specific genes, and a putative BFD1-binding motif is associated with differential expression. Identification of BFD1 as a master regulator of differentiation is a breakthrough in our understanding of the regulation of chronic Toxoplasma infection, and provides a molecular switch for further characterization of this clinically relevant transition.