Toxoplasma gondii
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ABSTRACT:
PROVIDER: PRJNA92953 | ENA |
REPOSITORIES: ENA
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Project description:Two forms of the protozoan parasite Toxoplasma gondii are associated with intermediate hosts such as humans: rapidly growing tachyzoites are responsible for acute illness, whereas slowly dividing encysted bradyzoites can remain latent within the tissues for the life of the host. In order to identify genetic factors associated with parasite differentiation, we have used a strong bradyzoite-specific promoter (identified by promoter trapping) to drive the expression of T. gondii hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) in stable transgenic parasites, providing a stage-specific positive/negative selectable marker. Insertional mutagenesis has been carried out on this parental line, followed by bradyzoite induction in vitro and selection in 6-thioxanthine to identify misregulation mutants. Two different mutants fail to induce the HXGPRT gene efficiently during bradyzoite differentiation. These mutants are also defective in other aspects of differentiation: they replicate well under bradyzoite growth conditions, lysing the host cell monolayer as effectively as tachyzoites. Expression of the major bradyzoite antigen BAG1 is reduced, and staining with Dolichos biflorus lectin shows reduced cyst wall formation. Microarray hybridizations show that these mutants behave more like tachyzoites at a global level, even under bradyzoite differentiation conditions. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. User Defined
2005-08-13 | E-GEOD-3119 | biostudies-arrayexpress
Project description:Two forms of the protozoan parasite Toxoplasma gondii are associated with intermediate hosts such as humans: rapidly growing tachyzoites are responsible for acute illness, whereas slowly dividing encysted bradyzoites can remain latent within the tissues for the life of the host. In order to identify genetic factors associated with parasite differentiation, we have used a strong bradyzoite-specific promoter (identified by promoter trapping) to drive the expression of T. gondii hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) in stable transgenic parasites, providing a stage-specific positive/negative selectable marker. Insertional mutagenesis has been carried out on this parental line, followed by bradyzoite induction in vitro and selection in 6-thioxanthine to identify misregulation mutants. Two different mutants fail to induce the HXGPRT gene efficiently during bradyzoite differentiation. These mutants are also defective in other aspects of differentiation: they replicate well under bradyzoite growth conditions, lysing the host cell monolayer as effectively as tachyzoites. Expression of the major bradyzoite antigen BAG1 is reduced, and staining with Dolichos biflorus lectin shows reduced cyst wall formation. Microarray hybridizations show that these mutants behave more like tachyzoites at a global level, even under bradyzoite differentiation conditions.
2005-07-21 | E-SMDB-1406 | biostudies-arrayexpress
Project description:Two forms of the protozoan parasite Toxoplasma gondii are associated with intermediate hosts such as humans: rapidly growing tachyzoites are responsible for acute illness, whereas slowly dividing encysted bradyzoites can remain latent within the tissues for the life of the host. In order to identify genetic factors associated with parasite differentiation, we have used a strong bradyzoite-specific promoter (identified by promoter trapping) to drive the expression of T. gondii hypoxanthine-xanthine-guanine phosphoribosyltransferase (HXGPRT) in stable transgenic parasites, providing a stage-specific positive/negative selectable marker. Insertional mutagenesis has been carried out on this parental line, followed by bradyzoite induction in vitro and selection in 6-thioxanthine to identify misregulation mutants. Two different mutants fail to induce the HXGPRT gene efficiently during bradyzoite differentiation. These mutants are also defective in other aspects of differentiation: they replicate well under bradyzoite growth conditions, lysing the host cell monolayer as effectively as tachyzoites. Expression of the major bradyzoite antigen BAG1 is reduced, and staining with Dolichos biflorus lectin shows reduced cyst wall formation. Microarray hybridizations show that these mutants behave more like tachyzoites at a global level, even under bradyzoite differentiation conditions. Set of arrays organized by shared biological context, such as organism, tumors types, processes, etc. Keywords: Logical Set
2005-08-13 | GSE3119 | GEO
Project description:Toxoplasma gondii is a globally distributed obligate intracellular parasite which can cause zoonotic toxoplasmosis with great harms. The average death time of mice that infected with Toxoplasma gondii RH strain tachyzoites recovered from the liquid nitrogen was shortened after multiple generations. It has been reported that the parasite is in a state of static virulence during cryopreservation and the virulence of the protozoan parasite can be enhanced after continuous passages in hosts under laboratory conditions. However, no research has been conducted to elucidate its biological mechanism. Herein, we sequenced the T. gondii transcriptome using RNA-Seq technology and performed de novo assembly to investigated the virulence factors expression changes by comparing gene expression profiles between incipiently recovered and completely resuscitated tachyzoites. Transcriptome analysis identified 1,951 differentially expressed transcripts in infected liver, of which 1,752 were significantly downregulated and 199 upregulated. We identified many differentially expressed proteins and genes, including serine/threonine kinase, calnexin, myosin and microtubule-associated protein which have previously been reported to be either involved in cell adhesion, parasite gliding or participate in cell invasion. The great majority of the virulence factors including microneme proteins, rhoptry proteins and dense granule proteins were upregulated in fully recovered tachyzoites. The enhanced virulence of recovered Toxoplasma gondii RH strain from the liquid nitrogen is associated with the up-regulated expression of MICs, ROPs and GRAs. Our data will facilitate future genomic research and in-depth annotation of Toxoplasma gondii RH strain genomes. This study provides a profile of the candidate genes that are suspected to be involved with virulence enhancement of recovered Toxoplasma gondii RH strain tachyzoites. Many further studies should be carried out to confirm the function of the candidate genes. Moreover, the preliminary identification of genes and pathways exhibiting differential expression in complete resuscitation stage may further our general understanding of virulence enhancement in this parasite.
2021-05-14 | GSE114386 | GEO
Project description:The lytic cycle of the protozoan parasite Toxoplasma gondii, which involves a brief sojourn in the extracellular space, is characterized by defined transcriptional profiles. For an obligate intracellular parasite that is shielded from the cytosolic host immune factors by a parasitophorous vacuole, the brief entry into the extracellular space is likely to exert enormous stress. Due to its role in cellular stress response, we hypothesize that translational control plays an important role in regulating gene expression in Toxoplasma during the lytic cycle. Unlike transcriptional profiles, insights into genome-wide translational profiles of Toxoplasma gondii are lacking. We have performed genome-wide ribosome profiling, coupled with high throughput RNA sequencing, in intracellular and extracellular Toxoplasma gondii parasites to investigate translational control during the lytic cycle. Results: Although differences in transcript abundance were mostly mirrored at the translational level, we observed significant differences in the abundance of ribosome footprints between the two parasite stages. Furthermore, our data suggest that mRNA translation in the parasite is potentially regulated by mRNA secondary structure and upstream open reading frames.
2017-11-23 | GSE99395 | GEO
Project description:Cells infected with the intracellular protozoan parasite Toxoplasma gondii undergo upregulation of pro-inflammatory cytokines, organelle redistribution, and protection from apoptosis. To examine the molecular basis of these and other changes, gene expression profiles of human foreskin fibroblasts infected with Toxoplasma were studied using human cDNA microarrays consisting of ~22,000 known genes and uncharacterized ESTs. Early during infection (1-2 h), <1% of all genes show a significant change in the abundance of their transcripts. Of the 63 known genes in this group, 27 encode proteins associated with the immune response. These genes are also upregulated by secreted, soluble factors from extracellular parasites indicating that the early response does not require parasite invasion. Later during infection, genes involved in numerous host cell processes, including glucose and mevalonate metabolism, are modulated. Many of these late genes are dependent on the direct presence of the parasite; i.e. secreted products from either the parasite or infected cells are insufficient to induce these changes. These results reveal several previously unknown effects on the host cell and lay the foundation for detailed analysis of their role in the host-pathogen interaction.
2005-09-19 | E-SMDB-562 | biostudies-arrayexpress
Project description:Tartrolon E is a pan anti-apicomplexan compound derived from a symbiotic bacteria of shipworms. The mechanism of action of the compound is unknown, and attempts to select parasite mutants resistant to the compound has been unsuccessful. In this study, RNAseq was performed on human foreskin fibroblast cells (HFF) infected with Toxoplasma gondii RH strain and treated with Tartrolon E to identify genes targeted by the compound.
2019-11-12 | GSE140197 | GEO
Project description:To identify accessible chromatin regions in the human host cells during Toxoplasma parasite infection (uninfected, RH-infected and Pru-infected human foreskin fibroblasts) and in the obligate intracellular parasite Toxoplasma gondii (Type 1 RH strain and Type 2 Pru strain), ATAC-seq was performed.
2022-09-30 | GSE209866 | GEO
Project description:The innate immune response of mucosal epithelial cells during pathogen invasion plays a central role in immune regulation in the gut. Toxoplasma gondii (T. gondii) is a protozoan intracellular parasite that is usually transmitted through oral infection. Although much of the information on immunity to T. gondii has come from intra-peritoneal infection models, more recent studies have revealed the importance of studying immunity following infection through the natural per-oral route. Oral infection studies have identified many of the key players in the intestinal response; however, they have relied on responses detected days to weeks following infection. Much less is known about how the gut epithelial layer senses and reacts during initial contact with the pathogen. Given the importance of epithelial cells during pathogen invasion, this study uses an in vitro approach to isolate the key players and examine the early response of intestinal epithelial cells during infection by T. gondii. We show that human intestinal epithelial cells infected with T. gondii elicit rapid MAPK phosphorylation, NF-κB nuclear translocation, and secretion of interleukin (IL)-8. Both ERK1/2 activation and IL-8 secretion responses were shown to be MyD88 dependent and TLR2 was identified to be involved in the recognition of the parasite regardless of the parasite genotype. Furthermore, we were able to identify additional T. gondii-regulated genes in the infected cells using a pathway-focused array. Together, our findings suggest that intestinal epithelial cells were able to recognize T. gondii during infection, and the outcome is important for modulating intestinal immune responses.
2009-09-17 | GSE18085 | GEO
Project description:Toxoplasma gondii is an obligate intracellular parasite that can cause serious opportunistic disease in the immunocompromised or through congenital infection. To progress through its life cycle, Toxoplasma relies on multiple layers of gene regulation that includes an array of transcription and epigenetic factors. Over the last decade, the modification of mRNA has emerged as another important layer of gene regulation called epitranscriptomics. Here, we report that epitranscriptomics machinery exists in Toxoplasma, namely the methylation of adenosines (m6A) in mRNA transcripts. We identified novel components of the m6A methyltransferase complex and determined the distribution of m6A marks within the parasite transcriptome. m6A mapping revealed the modification to be preferentially located near transcription termination sites within the consensus sequence, YGCAUGCR. Knockdown of the m6A writer enzyme METTL3 resulted in diminished m6A marks, loss of a target transcript, and a complete arrest of parasite replication. Furthermore, we examined the two proteins in Toxoplasma that possess YTH domains, which bind m6A marks, finding them to be integral members of the cleavage and polyadenylation machinery that catalyzes the 3’-end processing of pre-mRNAs. Together, these findings establish that the m6A epitranscriptome is essential for parasite viability by contributing to the processing of mRNA 3’-ends.
2021-07-19 | GSE165067 | GEO