TY - JOUR. T1 - The protozoan parasite Toxoplasma gondii targets proteins to dense granules and the vacuolar space using both conserved and unusual mechanisms. AU - Karsten, Verena. AU - Qi, Huilin. AU - Beckers, Con J.M.. AU - Reddy, Anita. AU - Dubremetz, Jean Francois. AU - Webster, Paul. AU - Joiner, Keith A.. PY - 1998/6/15. Y1 - 1998/6/15. N2 - All known proteins that accumulate in the vacuolar space surrounding the obligate intracellular protozoan parasite Toxoplasma gondii are derived from parasite dense granules. To determine if constitutive secretory vesicles could also mediate delivery to the vacuolar space, T. gondii was stably transfected with soluble Escherichia coli alkaline phosphatase and E. coli β-lactamase. Surprisingly, both foreign secretory reporters were delivered quantitatively into parasite dense granules and efficiently secreted into the vacuolar space. Addition of a glycosylphosphatidylinositol membrane anchor rerouted alkaline phosphatase to the parasite surface. ...
Toxoplasma gondii is a protozoan pathogen that produces severe disease in humans and animals. This obligate intracellular parasite provides an excellent model for the study of how such pathogens are able to invade, survive, and replicate intracellularly. DNA encoding chloramphenicol acetyltransferase was introduced into T. gondii and transiently expressed with the use of three vectors based on different Toxoplasma genes. The ability to introduce genes and have them efficiently and faithfully expressed is an essential tool for understanding the structure-function relation of genes and their products. ...
Matrajt, M.; Donald, R.G.K.; Singh, U.; Roos, D.S., 2002: Identification and characterization of differentiation mutants in the protozoan parasite Toxoplasma gondii
The obligate intracellular protozoan parasite Toxoplasma gondii infects humans and other warm-blooded animals and establishes a chronic infection in the central nervous system after invasion. Studies showing a positive correlation between anti-Toxopl
Tenter AM, Heckeroth AR, Weiss LM. Toxoplasma gondii: from animals to humans. Int J Parasitol. 2000; 30(12-13):1217-58. Rahimi MT, Mahdavi SA, Javadian B et al. High seroprevalence of Toxoplasma gondii antibody in HIV/AIDS individuals from North of Iran. Iran J Parasitol. 2015; 10(4):584-9. Sarvi S, Daryani A, Rahimi MT et al. Cattle toxoplasmosis in Iran: a systematic review and meta-analysis. Asian Pac J Trop Med. 2015; 8(2):120-6. Kazemi B, Bandehpour M, Maghen L et al. Gene cloning of 30 kDa Toxoplasma gondii tachyzoites surface antigen (SAG1). Iran J Parasitol. 2007; 2(2): 1-8. Dubey JP, Jones JL. Toxoplasma gondii infection in humans and animals in the United States. Int J Parasitol. 2008; 38(11):1257-78. Tekkesin N. Diagnosis of toxoplasmosis in pregnancy: a review. HOAJ Biol. 2012; 1(1): 9-12. Rahimi MT, Daryani A, Sarvi S et al. Cats and Toxoplasma gondii: A systematic review and meta-analysis in Iran. Onderstepoort J Vet Res. 2015;82(1):823. Chen J, Li ZY, Petersen E et al. DNA ...
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TY - JOUR. T1 - Functional and biophysical analyses of the class XIV Toxoplasma gondii Myosin D. AU - Herm-Götz, Angelika. AU - Delbac, Frêdêric. AU - Weiss, Stefan. AU - Nyitrai, Miklos. AU - Stratmann, Rolf. AU - Tomavo, Stanislas. AU - Sibley, L. David. AU - Geeves, Michael A.. AU - Soldati, Dominique. PY - 2006/2/1. Y1 - 2006/2/1. N2 - The obligate intracellular parasite Toxoplasma gondii uses gliding motility to migrate across the biological barriers of the host and to invade cells. This unique form of locomotion requires an intact actin cytoskeleton and involves at least one motor protein (TgMyoA) that belongs to the class XIV of the myosin superfamily. TgMyoA is anchored in the inner membrane complex and is essential for the gliding motion, host cell invasion and egress of T. gondii tachyzoites. TgMyoD is the smallest T. gondii myosin and is structurally very closely related to TgMyoA. We show here that TgMyoD exhibits similar transient kinetic properties as the fast single-headed ...
Toxoplasma gondii and Plasmodium species are obligate intracellular pathogens that utilize host sugars for energy homeostasis and macro molecular synthesis. Here, we report that the T. gondii glucose transporter, TgGT1, and of its homologs of P. falciparum and P. berghei (PfHT1 and PbHT1) transport glucose, mannose, galactose and fructose. Besides TgGT1, Toxoplasma harbours one additional surface localized putative sugar transporter (TgST2). Surprisingly both Proteins are nonessential and only the deletion of TgGT1 inflicts a mild defect in the parasite replication. The ?tggt1 mutant is unable to import glucose and consequently displays an attenuated glucose-dependent motility, which is completely rescued by glutamine. ?tggt1 performs increased glutamine metabolism that is sufficient to sustain motility and replication. The ?tggt1 strain provides a model for further investigating its adaptation to disparate host cells. In contrast to T. gondii, erythrocytic stages of Plasmodium species ...
Toxoplasmosis, a neglected tropical disease caused by the protozoan parasite Toxoplasma gondii, occurs throughout the world. Human T. gondii infection is asymptomatic in 80% of the population; however, the infection is life-threatening and causes substantial neurologic damage in immunocompromised patients such as HIV-infected persons. The major purpose of this study was to investigate the seroprevalence of T. gondii infection in subjects infected with HIV/AIDS in eastern China. Our findings showed 9.7% prevalence of anti-T. gondii IgG antibody in HIV/AIDS patients, which was higher than in intravenous drug users (2.2%) and healthy controls (4.7%), while no significant difference was observed in the seroprevalence of anti-Toxoplasma IgM antibody among all participants (P,0.05). Among all HIV/AIDS patients, 15 men (7.7%) and 10 women (15.9%) were positive for anti-T. gondii IgG antibody; however, no significant difference was detected in the seroprevalence of anti-Toxoplasma IgG antibody between ...
The obligate intracellular parasite Toxoplasma gondii, a member of the phylum Apicomplexa that includes Plasmodium spp., is one of the most widespread parasites and the causative agent of toxoplasmosis. Micronemal proteins (MICs) are released onto the parasite surface just before invasion of host ce …
Purpose: Toxoplasmosis is the most common cause of infectious retinochoroiditis. It is caused by the parasite Toxoplasma gondii, which affects both immune compromised and immune competent patients. The cytokine interferon gamma (IFNg) plays an important role in the inhibition of Toxoplasma growth. In some cell types (such as HeLa cells) IFNg induces the enzyme indoleamine 2,3-dioxygenase (IDO) leading to tryptophan depletion and restriction of Toxoplasma growth while other cell types restrict Toxoplasma growth through an unknown mechanism. Macrophages and other innate immunity cells that infiltrate the retina in ocular toxoplasmosis play an important role in fighting the infection but can also contribute to the inflammation in the eye. It is unclear how human macrophages inhibit Toxoplasma growth. The goal of this study is to determine how IFNg-stimulated human cells inhibit Toxoplasma replication.. Methods: An in vitro study using the MM6 and THP-1human macrophage cell lines was performed. ...
Females in various species typically avoid males infected with parasites, while parasite-free males advertise their status through conspicuous phenotypic traits. This process selects for heritable resistance and reduces direct exposure of the female to parasites. Coevolving parasites are likely to attempt to circumvent this obstacle. In this paper, we demonstrate a case of parasitic manipulation of host mate choice. We report that Toxoplasma gondii, a sexually transmitted infection of brown rats, enhances sexual attractiveness of infected males. Thus under some evolutionary niches, parasites can indeed manipulate host sexual signaling to their own advantage ...
Toxoplasma gondii, the causative agent of toxoplasmosis, is an obligate intracellular protozoan parasite that resides inside a parasitophorous vacuole. During infection, Toxoplasma actively remodels the transcriptome of its hosting cells with profound and coupled impact on the host immune response. We report that Toxoplasma secretes GRA24, a novel dense granule protein which traffics from the vacuole to the host cell nucleus. Once released into the host cell, GRA24 has the unique ability to trigger prolonged autophosphorylation and nuclear translocation of the host cell p38α MAP kinase. This noncanonical kinetics of p38α activation correlates with the up-regulation of the transcription factors Egr-1 and c-Fos and the correlated synthesis of key proinflammatory cytokines, including interleukin-12 and the chemokine MCP-1, both known to control early parasite replication in vivo. Remarkably, the GRA24-p38α complex is defined by peculiar structural features and uncovers a new regulatory signaling ...
Unlike Opisthokonta lineages (such as yeasts and metazoans), several otherwise conserved key components of mRNA export are not found in the genomes of the Chromalveolata and Excavata lineages, including several species of parasites [11, 12]. Our bioinformatic analysis of Apicomplexa (Additional file 1: Table S1) corroborates previous work suggesting the presence of either highly divergent or unique components for mRNA export in these parasites. Figure 1b shows an overview of the few conserved components of mRNA export in the Apicomplexa, and the relevance of those findings are discussed below.. The major and specific mRNA complex (TREX) may not be conserved in the genomes of the three apicomplexan parasites we analyzed. These genomes contain only a homolog for UAP56 and lack a homolog for REF/Aly as well as for most THO complex components, with the exception of Tho2 (Additional file 1: Table S1). Similar to TREX, several homologs for components of the TREX-2 complex were not identified in these ...
TY - JOUR. T1 - Effects of Cold Stress on Spleen Cell Proliferation and Cytokine Production during Chronic Toxoplasma gondii Infection. AU - Aviles, Hernan. AU - Johnson, Mary T.. AU - Monroy, Fernando P. PY - 2004. Y1 - 2004. N2 - Background: Cell-mediated immunity is critical for controlling infection and preventing reactivation during the chronic phase of Toxoplasma gondii infection. In people suffering from AIDS, T. gondii is one of the major opportunistic infectious agents. Mechanisms regulating rapid development of clinical signs in previously asymptomatic patients remain unclear; however, cofactors such as stress are suspected to play a role in the susceptibility to opportunistic infections. Objective: This study examined the role of cold stress (CS) in splenocyte function during chronic T. gondii infection. Methods: Control mice and mice previously infected orally with T. gondii were subjected to CS during the chronic phase (CSchr), i.e. 90 days after infection, and in vitro cell ...
Immunity Related Guanosine Triphosphatases or IRGs are proteins activated as part of an early immune response. IRGs have been described in various mammals but are most well characterized in mice. IRG activation in most cases is induced by an immune response and leads to clearance of certain pathogens. Interferon (IFN)-inducible GTPases encompass four families of proteins including myxovirus resistant proteins (Mx), guanylate-binding proteins (GBP), immunity-related GTPase proteins (IRGs), and very large inducible GTPase proteins (VLIG). IRGs confer resistance from vacuolar pathogens by localizing to and disrupting the phagocytic vacuole during infection. The activation of IRGs in mice is induced by interferon. IRG genes have been identified in various vertebrates and some invertebrates. They are involved in important immune defenses against intracellular pathogens and as a result have become a target for immune evasion by those pathogens. The intracellular protozoan parasite Toxoplasma gondii ...
The aim of this study was to evaluate the potential diagnostic usefulness of the full-length recombinant Toxoplasma gondii MAG1 protein by determining the levels of specific IgM and IgG antibodies in mouse and human sera obtained from individuals with acute and chronic toxoplasmosis. The obtained results revealed that IgG antibodies against MAG1 are a sensitive and specific marker of T. gondii infection since the protein was recognized by both mouse and human sera, 100% and 94.3%, respectively, rendering the full-length rMAG1 a prospective alternative for the polyvalent native antigen (TLA).. Keywords: Toxoplasma gondii, diagnostics of toxoplasmosis, ELISA, MAG1 antigen. Clinical diagnosis of Toxoplasma gondii infection, one of the most common parasitic zoonoses worldwide, relies primarily on a two-step procedure involving detection of specific antibodies (mostly IgM and IgG) and consecutive estimation of IgG avidity to distinguish between acute and chronic invasion in individuals with ...
Toxoplasmosis is a curable but potentially fatal disease [22]. Over the years, infection with the protozoan parasite Toxoplasma gondii has been proven to be one of the most common parasitic infections of man and other warm-blooded animals [2]. In this study, we sought to investigate Toxoplasma infection, as evidenced by anti-Toxoplasma antibodies in the serum of women of child bearing age in a rural locality in Cameroon. Our findings revealed that the seroprevalence of anti-T. gondii antibodies among the women of child-bearing age in this study was 54.5 %. This prevalence was similar to that obtained among women of child-bearing age in Timis, Romania (57.6 %) [23], but far lower than that found in women of child-bearing age in Central Ethiopia (81.4 %) [24]. This lower prevalence could be attributed to a lower cat density (10/178, Table 1) and consequent oocysts shedding and a lower consumption of unpasteurised milk in our study area. The seroprevalence obtained in this study is also far lower ...
Toxoplasma gondii is an obligate intracellular parasite often found in the brain of humans. Research has shown a correlation between prevalence of antibody titers to T. gondii and psychological illness in humans. Recent studies indicate that individuals seropositive for T. gondii antibodies are more likely to develop psychotic disorders including schizophrenia, which is associated with changes in the dopamine neurotransmitter system. Dopamine in the brain may play a role in proliferation, chemoattraction, infection efficiency, or stage conversion of T. gondii. Because tachyzoites are the first developmental stage to reach the brain, the present study was conducted to determine the effects of dopamine on their development in vitro. In human fibroblast host cells, dopamine was added at either 100 nM or 250 nM to cell culture media, and the numbers of tachyzoites produced at 48 hr were determined and compared to vehicle-treated controls. An increase of tachyzoite numbers and increased destruction ...
TY - JOUR. T1 - Pleiotropic effect due to targeted depletion of secretory rhoptry protein ROP2 in Toxoplasma gondii. AU - Nakaar, Valerian. AU - Ngô, Huân M.. AU - Aaronson, Emily P.. AU - Coppens, Isabelle. AU - Stedman, Timothy T.. AU - Joiner, Keith A. PY - 2003/6/1. Y1 - 2003/6/1. N2 - Long after their discovery, the function and biogenesis of rhoptries remain enigmatic. In Apicomplexan parasites, these organelles discharge and their contents are exocytosed at the time of host cell invasion, and are thus proposed to play an essential role in establishing the parasitophorous vacuole. In Toxoplasma gondii, ROP2 is suspected to serve as the molecular link between host cell mitochondria and parasitophorous vacuole membrane. In this study we addressed the function of ROP2. Targeted depletion of ROP2 using a ribozyme-modified antisense RNA strategy resulted in multiple effects on parasite morphology because of a disruption in the formation of mature rhoptries, and an arrest in cytokinesis. The ...
Toxoplasma gondii is an opportunistic protozoan closely associated with AIDS and vertical transmission. T. gondii actin depolymerizing factor (TgADF) plays an important role in actin cytoskeleton remodeling, and it is required to invade host cells. TgADF was a promising vaccine candidate. To observe the immunological changes and protective efficacy of recombinant TgADF protein (rTgADF) against T. gondii infection, we optimized the intranasal immunization dose of rTgADF and analyzed the survival rate and tachyzoite loads in mouse tissues after oral challenge with T. gondii tachyzoites. rTgADF was prepared, purified, and combined with mouse anti-His antibody and rabbit anti-T. gondii serum. After intranasal immunization with 10 μg, 20 μg, 30 μg, or 40 μg of rTgADF, the 30-μg group elicited high levels of secretory IgA (sIgA) in nasal, intestinal, and vesical washes, raised IgG titres in the sera, strong proliferation of splenocytes, and increased secretion of IL-2 and IFN
Purpose: : Toxoplasma gondii is an intracellular protozoan parasite and the most common cause of infectious posterior uveitis. Cytokines play an important role in the regulation of T.gondii infection. This study was conducted to evaluate the in vitro effect of alpha tumor necrosing factor (TNF-α) and gamma interferon (INF-γ) in rat retinal cells infection by Toxoplasma gondii. Methods: : Rat retinal cells - retinal pigment epithelial cells (RPE) and retinal Müller glial (RMG) cells - were in vitro infected by Toxoplasma gondii RH strain tachyzoïtes. Culture cells were stimulated with TNF-α, INF-γ, and LPS, alone at different concentrations, or in combination. The effect of TNF-α and INF-γ in T.gondii invasion and replication between retinal cells was evaluated by two different methods : measurement of [3H]-uracil incorporation and counting infected cells under microscopic examination. Cells nitric oxide (NO) production was also evaluated. Results: : IFN-γ significantly inhibits ...
BACKGROUND In addition to helminthic infections, elevated serum IgE levels were observed in many protozoal infections, while their contribution during immune response to these pathogens remained unclear. As IgE/antigen immune complexes (IgE-IC) bind to human cells through FcεRI or FcεRII/CD23 surface molecules, the present study aimed to identify which functional receptor may be involved in IgE-IC interaction with human macrophages, the major effector cell during parasite infection. METHODOLOGY/PRINCIPAL FINDINGS Human monocyte-derived macrophages were infected with Toxoplasma gondii before being incubated with IgE-IC. IgE receptors were then identified using appropriate blocking antibodies. The activation of cells and parasiticidal activity were evaluated by mediator quantification and direct counting of infected macrophages. RNAs were extracted and cell supernatants were also collected for their content in tumor necrosis factor (TNF)-α, interleukin-10 (IL-10) and nitrites. Sera from symptomatic
The protozoan parasite Toxoplasma gondii has a complex life cycle involving the developmental transition between the asexual exo-enteric stages (tachyzoites and bradyzoites) and the coccidian (sexual and asexual) forms (schizonts, macrogametes and microgametes). Previous work has established the stage-specific expression of certain proteins including two glycolytic isoenzymes of enolase and lactate dehydrogenase in T. gondii. Here we describe the expression and subcellular localisation of the two isoforms of enolase (ENO1 and ENO2) and lactate dehydrogenase (LDH1 and LDH2) in vivo using immunocytochemistry. In mice, proliferating parasites in the lung expressed ENO2 and LDH1 and were characterised as tachyzoites by the presence of a tachyzoite specific surface antigen (SAG1). In contrast, ENO1 and LDH2 were expressed by bradyzoites present in tissue cysts in the brain characterised by the presence of the bradyzoite specific antigen (BAG1). During stage conversion (tachyzoite/bradyzoite), the isoenzyme
OGENDI, Edwin et al. Questionnaire Survey on the Occurrence of Risk factors for Toxoplasma gondii infection amongst Farmers in Thika District, Kenya. J. S. Afr. Vet. Assoc. [online]. 2013, vol.84, n.1, pp.00-00. ISSN 2224-9435.. A survey was conducted to determine the occurrence of risk factors for Toxoplasma gondii infection amongst farmers in Thika District, Kenya. Interviews were conducted in a total of 385 households using a structured questionnaire. The water consumed at household level originated from taps (74.3%), rivers or streams (15.1%), wells (5.4%) and boreholes (5.2%). A number of households (46.8%) consumed water without boiling or applying any form of treatment. All respondents washed vegetables before cooking, whilst 99.0% washed fruits before eating. Boiled milk was preferred by 99.5% of the farmers. The majority (85.2%) consumed beef more often, whilst 1.6% consumed pork. The majority (98.7%) consumed thoroughly cooked meat. Meat was preserved by 17% of farmers. Only four ...
Classical treatment for congenital toxoplasmosis is based on combination of sulfadiazine and pyrimethamine plus folinic acid. Due to teratogenic effects and bone marrow suppression caused by pyrimethamine, the establishment of new therapeutic strategies is indispensable to minimize the side effects and improve the control of infection. Previous studies demonstrated that enrofloxacin and toltrazuril reduced the incidence of Neospora caninum and Toxoplasma gondii infection. The aim of the present study was to evaluate the efficacy of enrofloxacin and toltrazuril in the control of T. gondii infection in human trophoblast cells (BeWo line) and in human villous explants from the third trimester. BeWo cells and villous were treated with several concentrations of enrofloxacin, toltrazuril, sulfadiazine, pyrimethamine, or combination of sulfadiazine+pyrimethamine, and the cellular or tissue viability was verified. Next, BeWo cells were infected by T. gondii (2F1 clone or the ME49 strain), whereas villous
The protozoan parasite Toxoplasma gondii (T. gondii) is an important zoonotic pathogen, which has the ability to infect all warm blooded mammals including humans, with approximately one third of the human population predicted to be infected. Transmission of the parasite to the foetus during pregnancy can result in miscarriage, however, a child infected during pregnancy may go on to develop clinical symptoms such as retinochoroiditis (ocular toxoplasmosis), hydrocephalus or learning difficulties in later life. Post-natally acquired infection in humans is generally asymptomatic, however, individuals who are immunocompromised may develop ocular toxoplasmosis or toxoplasmic encephalitis. T. gondii type II is reported to be the predominant genotype in Europe and the United States, but currently very little information exists about the prevalence and genotypes present within Great Britain. Consumption of T. gondii tissue cysts from raw or undercooked meat is a main source of infection for humans, with ...
Citation: Dubey, J.P. 2013. The history and life cycle of Toxoplasma gondii. In: Weiss, L.M. and Kim, K., editors. Toxoplasma gondii, The model apicomplexan: Perspective and methods. 2nd edition. Waltham, MA: Elsevier. p. 1-14. Interpretive Summary: Toxoplasma gondii is a single-celled parasite of all warm-blooded hosts worldwide. It causes mental retardation and loss of vision in children, and abortion in livestock. Cats are the main reservoir of T. gondii because they are the only hosts that can excrete the resistant stage (oocyst) of the parasite in the feces. Humans become infected by eating under cooked meat from infected animals and food and water contaminated with oocysts. In the present paper the author reviews life cycle of Toxoplasma. The results will be of interest to biologists, parasitologists, and public health workers. Technical Abstract: Infections by the protozoan parasite Toxoplasma gondii are widely prevalent in humans and other animals on all continents. There are many ...
ABSTRACT. Munhoz A.D., Bandarra M.B., Vasconcelos R.O., Mineo T.W.P. & Machado R.Z. Use of embryonated egg membranes in the standardization of immunohistochemistry protocols for Toxoplasma gondii. [Utilização de membranas de ovos embrionados na padronização de protocolos de imunohistoquímica de Toxoplasma gondii.] Revista Brasileira de Medicina Veterinária 36(4):401-404, 2014. Departamento de Patologia Animal, Universidade Estadual Julio Mesquita Filho, Unesp/Jaboticabal, Rod. Paulo Castellane s/n, Jaboticabal, São Paulo, SP 14884-900, Brazil. E-mail: [email protected] The chorioallantoic membranes of embryonated eggs can be used in the standardization of immunohistochemistry (IHC) protocols to detect Toxoplasma gondii antigens. On the 10th day of embryogenesis, four groups received, respectively, 1x104 , 1x105 , 5x105 and 1x106 T. gondii tachyzoites (RH strain)/ 100 µL, and a control group received PBS (pH 7.2). Three forms of heat induced antigen retrieval were employed (double ...
Toxoplasmosis is caused by the protozoan parasite Toxoplasma gondii. In various places throughout the world, it has been shown that up to 95% of some populations have been infected with Toxoplasma, but very few have symptoms because the immune system usually keeps the parasite from causing illness. However, women newly infected with T. gondii during pregnancy and anyone with a compromised immune system should be aware that toxoplasmosis can have severe consequences. Toxoplasmosis is not passed from person-to-person, except in instances of mother-to-child (congenital) transmission and blood transfusion or organ transplantation. People typically become infected by three principal routes of transmission: Foodborne, animal to human (zoonotic) and mother to child (congenital).. ...
Toxoplasma gondii is an obligate intracellular parasite of great veterinary and medical importance. It is able to evade the immune system of the host by converting from rapidly proliferating tachyzoites to latent bradyzoite cysts and this parasite number control is a key to the success of the infection. Pathways controlling cell division/proliferation like the Hippo pathway are likely candidates for regulating parasite replication. Human Mob1 participates in this pathway and our recent data suggests it is an excellent candidate for the control of parasite replication/number. Our research group has identified a single mob1 gene in T. gondii. A phylogenetic analysis of this gene showed it to be similar to other Apicomplexa but distant from protozoan parasites like the Trypanosomatida. We confirmed that this gene is expressed and our data show that its expression dramatically decreases (94%) during the parasite replication inside the host cell. We have constructed a transgenic parasite strain that ...
Objective(s): The protozoan Toxoplasma gondii as an intracellular protozoan is widely prevalent in humans and animals. Infection generally occurs through consuming food contaminated with oocysts and tissue cysts from undercooked meat. The parasite is carried in sexual fluids like semen but there is little information about the effect of T. gondii on the male reproductive system. In this study, we examined the effect of T. gondii tachyzoites on apoptosis induction in type B spermatogonia (GC-1) cells.Materials and Methods: Fresh tachyzoites taken of infected BALB/c mice, GC-1 spg cells were infected with increasing concentrations of tachyzoites of T. gondii, then apoptotic cells were identified and quantified by flow cytometry. The genes associated with apoptosis were evaluated by RT2 Profiler PCR Array.Results: PCR array analysis of 84 apoptosis-related genes demonstrated that 12 genes were up-regulated at least 4-fold and that one gene was down-regulated at least 2-fold in the T. gondii infection group
Background: Toxoplasma gondii is an obligate intracellular parasite, which can infect all nucleated cells in a variety of vertebrate animals, including human, causing toxoplasmosis. Although a number of studies have reported on the seroprevalence of T. gondii infection in dogs in China, however, information about T. gondii infection in pet dogs in Anhui, China is not available.. Methods: The modified agglutination test (MAT) was used to detect antibodies in sera samples from 468 pet dogs at Anhui Province in China from November 2013 to April 2017.. Results: 18.6% animals were T. gondii seropositive, indicating a slightly higher prevalence of T. gondii infection in pet dogs in Anhui, China in comparison with other provinces in China.. Conclusion: Our present study provided epidemiological data on T. gondii seroprevalence in pet dogs in Anhui, China for the effective prevention and control of the parasite prevalence in this area.. ...
Background and aims: Toxoplasmosis, a zoonotic parasitic disease of warm-blooded animals, is notably influenced by environmental features. Recognizing spatial pattern of Toxoplasma gondii distribution in environment can provide significant contributions to public health and toxoplasmosis control. This study was designed to survey the frequency of T. gondii antibody in rural dogs and cats and also analyze possible relation between environmental factors and spatial distribution of T. gondiiantibody in Golestan province, using GIS. Methods: From 2015 to 2016, 106 rural cats and 154 rural dogs were randomly sampled. Serum samples were tested for presence of T. gondii antibody through modified agglutination test (MAT). The relation between T. gondii antibody frequency and environmental factors was surveyed in ArcGIS and Idrisi Selva software with multiple linear regression model. Results: From sampled rural cats and rural dogs, 85 (80.1%) and 99 (64.2%) were positive for T. gondii antibody, respectively.
Background: Toxoplasma gondii is an obligate intracellular protozoan parasite that infects humans and a broad spectrum of warm-blooded vertebrates. The present study was undertaken with the objectives of isolation and determining the genotypes of T. gondii strains from sheep and goats slaughtered in East and West Shewa Zones of Oromia Regional State, Central Ethiopia. Methods: Hearts of 47 sheep and 44 goats that were seropositive in the Direct Agglutination Test (DAT) were bioassayed in mice. A multiplex PCR assay with 15 microsatellite markers was employed for genotyping of T. gondii isolates from sheep and goats. Results: Viable T. gondii were isolated from 47 (51.65%) animals, 27 sheep and 20 goats. Most isolates caused sub-clinical infections in mice, however, 2 sheep and 1 goat isolates were mouse-virulent, killing mice between 19-27 days post-inoculation. The success of T. gondii isolation in mice increased significantly (P = 0.0001) with higher DAT antibody titers in sheep and goats. Genotyping
Although microRNAs (miRNAs) play an important role in liver homeostasis, the extent to which they can be altered by Toxoplasma gondii infection is unknown. Here, we utilized small RNA sequencing and bioinformatic analyses to characterize miRNA expression profiles in the liver of domestic cats at 7 days after oral infection with T. gondii (Type II) strain. A total of 384 miRNAs were identified and 82 were differentially expressed, of which 33 were up-regulated and 49 down-regulated. Also, 5690 predicted host gene targets for the differentially expressed miRNAs were identified using the bioinformatic algorithm miRanda. Gene ontology analysis revealed that the predicted gene targets of the dysregulated miRNAs were significantly enriched in apoptosis. Kyoto Encyclopedia of Genes and Genomes analysis showed that the predicted gene targets were involved in several pathways, including acute myeloid leukemia, central carbon metabolism in cancer, choline metabolism in cancer, estrogen signaling pathway, ...
The highly prevalent parasite Toxoplasma gondii manipulates its hosts behavior. In infected rodents, the behavioral changes increase the likelihood that the parasite will be transmitted back to its definitive cat host, an essential step in completion of the parasites life cycle. The mechanism(s) responsible for behavioral changes in the host is unknown but two lines of published evidence suggest that the parasite alters neurotransmitter signal transduction: the disruption of the parasite-induced behavioral changes with medications used to treat psychiatric disease (specifically dopamine antagonists) and identification of a tyrosine hydroxylase encoded in the parasite genome. In this study, infection of mammalian dopaminergic cells with T. gondii enhanced the levels of K+-induced release of dopamine several-fold, with a direct correlation between the number of infected cells and the quantity of dopamine released. Immunostaining brain sections of infected mice with dopamine antibody showed intense
Toxoplasma gondii is an obligate intracellular protozoan parasite that causes congenital toxoplasmosis, as well as other serious clinical presentations in immune compromised humans. The parasite has also been recently linked to behavioral diseases in humans and other mammalian hosts. New antigens are being evaluated to develop a diagnostic kit for the diagnosis of acute infection or a protective vaccine. In this study, we have focused on the discovery of new antigenic proteins from T. gondii genomic data using a high throughput protein microarray screening. To date, microarrays containing | 2870 candidate exon products of T. gondii have been probed with sera collected from patients with toxoplasmosis. Here, the protein microarrays are probed with well-characterized serum samples from animal models administered orally with oocysts or tissue cysts. The aim was to discover the antigens that overlap in the mouse profile with human antibody profiles published previously. For this, a reactive antigen list of
The obligate intracellular parasite Toxoplasma gondii exhibits closed mitosis, as chromosome segregation occurs with the confines of the nuclear envelope. Distinct structural changes are absent during mitosis, as the nucleolus is maintained and condensation of chromosomes is largely restricted. Moreover, the centromeres are clustered and remain persistently associated with the centrocone (spindle pole). To elucidate the process of chromosome segregation during mitosis in the parasite, the role of kinetochores and microtubules was examined. Localization studies of the functionally conserved kinetochore proteins TgNuf2 and TgNdc80 revealed that clustered kinetochores colocalize with clustered centromeres at the centrocone throughout the cell cycle. Pharmacological disruption of microtubules resulted in partial loss of clustering, which indicates spindle microtubules are necessary, but not strictly required for this process. Furthermore, the generation of a conditional TgNuf2 knockdown revealed this
Toxoplasma gondii, an obligate intracellular protozoan parasite, possesses the remarkable ability to co-opt host cell machinery in order to maintain its intracellular survival. This parasite can modulate signaling pathways of its host through the secretion of polymorphic effector proteins localized in the rhoptry and dense granule organelles. One of such effectors is T. gondii type II-specific dense granule protein 15, TgGRA15, which activates NF-κB pathway. The aim of the present study was to identify the host interaction partner proteins of TgGRA15 ...
Background: P35 and P22 Toxoplasma gondii proteins are recognized by specific IgG at the early infection stage, making them ideal for acute toxoplasmosis pregnancy control. Both proteins have been studied to discriminate between acute and chronic toxoplasmosis. However, results were hardly comparable because different protein obtainment procedures led to different antigens, the referencepanels used were not optimally typified, and avidity tests were either not performed or narrowly examined. Methods: We bioinformatically predicted P35 andP22 regions with the highest density of epitopes, and expressed them in pET32/BL21DE3 alternative expression system, obtaining the soluble proteins rP35a and rP22a. We assessed their diagnostic performance using pregnant woman serum samples typified as: not infected, NI (IgG−, IgM−), typical-chronic, TC (IgM−, IgG+), presumably acute, A (IgG+, IgM+, low-avidity IgG), and recentlychronic, RC (IgG+, IgM+, high-avidity IgG ...
BONAPAZ, Rubia dos Santos et al. Effects of infection with Toxoplasma gondii oocysts on the intestinal wall and the myenteric plexus of chicken (Gallus gallus). Pesq. Vet. Bras. [online]. 2010, vol.30, n.9, pp.787-792. ISSN 0100-736X. http://dx.doi.org/10.1590/S0100-736X2010000900013.. This paper aims to analyze the effects of the Toxoplasma gondii infection in the intestinal wall and myenteric plexus of chicken (Gallus gallus). Ten 36-day-old chickens were separated into two groups: control and experimental, orally inoculated with oocysts of the T. gondii strain M7741 genotype III. After 60 days the birds were submitted to euthanasia and had their duodenum removed. Part of the intestinal segments was submitted to histological routine, HE staining, PAS histochemical technique, and Alcian Blue. Qualitative analysis of the intestinal wall and comparative measurements among the groups with respect to total wall thickness, muscle tunic, mucosa, and tunica mucosa were carried out. Caliciform cells ...
TY - JOUR. T1 - An improved method for introducing site-directed point mutation into the Toxoplasma gondii genome using CRISPR/Cas9. AU - Sugi, Tatsuki. AU - Kato, Kentaro. AU - Weiss, Louis M.. N1 - Publisher Copyright: © 2016 Elsevier Ireland Ltd Copyright: Copyright 2018 Elsevier B.V., All rights reserved.. PY - 2016/10. Y1 - 2016/10. N2 - Toxoplasma gondii is an obligate intracellular parasite in the phylum Apicomplexa. Due to the ease of genetic manipulations in T. gondii it serves as a model organism for intracellular parasites. We utilized CRISPR/Cas9, which can be designed to target a specific genomic locus, to introduce site-directed point mutations directly into the T. gondii genomes. This paper contains step-by-step protocols for: (1) designing the guide RNA sequence; (2) constructing the CRISPR/Cas9 construct for a target gene and preparing a donor sequence; and (3) transfecting the CRISPR/Cas9 modules into the parasite and selecting the parasite with the desired point mutation. In ...
Toxoplasma gone/// is a parasite discovered in 1908 by Nicolle and Manceaux; they found a protozoan in tissue of a hamster-like rodent in laboratory of the Charles Nicolle at the Pasteur Institute in Tunisia. It is an obligate intracellular protozoan parasite, capable of infecting most species of warm-blooded vertebrates including mammals and birds. This infection is world-wide and one third of the human population is infected chronically. Toxoplasmosis is an important disease and a causative agent that is responsible for abortion in human and farm animals. T. gondii can be transmitted in three ways: via cat faeces, eating raw meat and congenital transmission (mother to child). To investigate transmission routes and prevalence of T. gondii in human in Libya a set of human tissues samples (umbilical cord) were collected at birth using suitable ethical procedures. One hundred fifty three umbilical cord samples were collected from volunteer subjects in Misurata Central Hospital and Alsaed Hospital ...
TY - JOUR. T1 - Structure of Toxoplasma gondii LDH1. T2 - Active-Site Differences from Human Lactate Dehydrogenases and the Structural Basis for Efficient APAD+ Use. AU - Kavanagh, Kathryn L.. AU - Elling, Robert A.. AU - Wilson, David K.. PY - 2004/2/3. Y1 - 2004/2/3. N2 - While within a human host the opportunistic pathogen Toxoplasma gondii relies heavily on glycolysis for its energy needs. Lactate dehydrogenase (LDH), the terminal enzyme in anaerobic glycolysis necessary for NAD+ regeneration, therefore represents an attractive therapeutic target. The tachyzoite stage lactate dehydrogenase (LDH1) from the parasite T. gondii has been crystallized in apo form and in ternary complexes containing NAD + or the NAD+-analogue 3-acetylpyridine adenine dinucleotide (APAD+) and sulfate or the inhibitor oxalate. Comparison of the apo and ternary models shows an active-site loop that becomes ordered upon substrate binding. This active-site loop is five residues longer than in most LDHs and necessarily ...
Toxoplasma, a human pathogen and a model apicomplexan parasite, actively and rapidly invades host cells. To initiate invasion, the parasite induces the formation of a parasite-cell junction, progressively propels itself through the junction inside a newly formed vacuole that encloses the entering parasite. Litle is known how a few micron-large diameter parasite overcome the host cell cortical actin barrier to support these remarkably rapid process of internalization (, few seconds). Correlative light and electron microscopy in conjunction with electron tomography and three-dimensional image analysis indicate that toxofilin an actin-binding protein, secreted by invading parasites correlates with localized sites of disassembly of the host cell actin meshwork. Moreover, quantitative fluorescence speckle microscopy in cells expressing toxofilin indicates that toxofilin regulates actin filament disassembly and turnover. Furthermore, Toxoplasma tachyzoites lacking toxofilin, are impaired in cortical ...
Background: Toxoplasma gondii infections are prevalent in humans and animals throughout Libya. Current diagnosis is based on detection of Toxoplasma-specific IgM and IgG. In this study, we established and optimized a diagnostic PCR assay for molecular diagnosis of T. gondii in Libya. Methods: From January to December, 2010, 177 blood and serum samples were collected from suspected patients. This includes: 140 women who have had spontaneous abortions, 26 HIV-positive patients, nine patients with leukemia and lymphoma, and two infants with ocular infection. Samples were screened for anti-Toxoplasma IgG and IgM antibodies before DNA extraction. The surface antigen gene 2 (SAG2) was targeted in a semi-nested PCR to amplify a 999 bp and a 614 bp fragment in the first and the second run respectively. Results: A total of 54/140 (38.5 %) women who have had spontaneous abortions, 23/26 (88 %) HIV patients, 6/9 (66.6 %) of the leukaemia and lymphoma patients, and one child with ocular infection were ...
Toxoplasma gondii like oocysts were detected in 4% of cat feces using light microscopy in Kunming, China. Amplicon was generated from these oocysts using a T. gondii-but not Hammondia hammondi-specific primer set. Cat and KM mouse were susceptible to infection by these T. gondii-like oocysts. Tissue cysts were found in the brain of the experimentally infected animals and were infective to mouse, indicating that the T. gondii-like oocysts isolated from naturally infected cats had a facultative secondary host life cycle. Comparison of GRA6 and SAG2 sequences with those of reference strains indicated that the cat-derived T. gondii (KM isolate) were typical of T. gondii genotype II. This is the first report of isolation, identification, and genotyping of T. gondii from feline feces in China. The occurrence of oocyst shedding in the cat population studied was higher than that found in most cat populations world-wide, which strongly implies the need for further studies of population genetic structure ...
Risky business: linking Toxoplasma gondii infection and entrepreneurship behaviours across individuals and countries Journal Article ...
Infection with Toxoplasma gondii in brain may cause some symptoms that resemble those in women with premenstrual syndrome. To determine the association of T. gondii infection with symptoms and signs of premenstrual syndrome, we examined 489 women aged 30-40 years old. Sera of participants were analyzed for the presence of anti-Toxoplasma IgG and IgM antibodies using enzyme-linked immunoassays (EIA) and T. gondii DNA by polymerase chain reaction (PCR). Anti-T. gondii IgG antibodies were found in 38 (7.8%) of the women studied. Anti-T. gondii IgM antibodies were found in 13 (34.2%) of the 38 IgG seropositive women. Logistic regression showed two variables associated with seropositivity to T. gondii: presence of diarrhea (odds ratio [OR] = 6.10; 95% confidence interval [CI]: 1.37-27.85; P = 0.01) and weight gain (OR = 2.89; 95% CI: 1.37-6.07; P = 0.005), and two variables associated with high (>150 IU/ml) levels of IgG against T. gondii: presence of diarrhea (OR = 7.40; 95% CI: 1.79-30.46; P = ...
Toxoplasma gondii is an important opportunistic agent especially in immunocompromised hosts and can cause significant morbidity and mortality. Hence, detection and monitoring of anti-Toxoplasma antibodies are of a great interest in HIV-infected patients. A study on the prevalence of toxoplasmosis and associated risk factors was carried out among HIV-infected patients in Jahrom, southern Iran. The prevalence of anti-Toxoplasma IgG antibodies was 21.1% in HIV-infected patients by ELISA. PCR was performed on all of the samples, and 1 of the blood samples was positively detected. Among the HIV patients, anti-Toxoplasma IgG antibodies were significantly higher in age group of 30-39 years old (P=0.05). The seroprevalence of toxoplasmosis in patients with CD4+|100 cells/μl was 33.3% that was significantly higher than the other groups (P=0.042) with or without IgG antibodies. The CD4+ count mean of seropositive patients was lower than that of seronegative patients. The seroprevalence of toxoplasmosis in
The widespread protozoan parasite Toxoplasma gondii interferes with host cell functions by exporting the contents of a unique apical organelle, the rhoptry. Among the mix of secreted proteins are an expanded, lineage-specific family of protein kinases termed rhoptry kinases (ROPKs), several of which have been shown to be key virulence factors, including the pseudokinase ROP5. The extent and details of the diversification of this protein family are poorly understood. In this study, we comprehensively catalogued the ROPK family in the genomes of Toxoplasma gondii, Neospora caninum and Eimeria tenella, as well as portions of the unfinished genome of Sarcocystis neurona, and classified the identified genes into 42 distinct subfamilies. We systematically compared the rhoptry kinase protein sequences and structures to each other and to the broader superfamily of eukaryotic protein kinases to study the patterns of diversification and neofunctionalization in the ROPK family and its subfamilies. We identified
We report on apparent temporal progression of probable sources of infection and transmission routes for global human toxoplasmosis outbreaks as described in published articles. We searched the Scientific Electronic Library Online, Web of Science, PubMed, and Scopus databases for articles on Toxoplasma, toxoplasmosis, and outbreaks. We found that transmission routes for Toxoplasma gondii varied by decade. In the 1960s and 1990s, toxoplasmosis outbreaks mainly occurred through ingestion of cysts in meat and meat derivatives; in the 1980s, through milk contaminated with tachyzoites; in 2000, due to the presence of oocysts in water, sand, and soil; and in 2010, due to oocysts in raw fruits and vegetables. Our study suggests a possible change in the epidemiology of reported toxoplasmosis outbreaks. Because of this change, we suggest that greater attention be paid to the disinfection of vegetables, as well as to the quality of water used for drinking and irrigation.
Toxoplasma gondii is an infective parasite that causes reproductive disorders such as abortion, fetal mummification, birth of weak offspring, and stillbirth, thereby causing economic losses to sheep production. The northeastern region of Brazil has approximately 171 million small ruminants, of which 5.4% are sheep. The present study aimed at determining the rate of occurrence of T. gondii in sheep flocks on 60 farms in 19 municipalities in the three mesoregions (eastern, semi-arid, and sertão or backlands) of the state of Sergipe, Brazil, and the risk factors associated with this infection. Serum samples were collected between 2011 and 2012, from 60 farms located in 19 municipalities in the three mesoregions: 680 in the eastern region, 280 in the semi-arid region, and 240 in the backlands, totaling 1,200 samples (990 females and 210 males). Anti-T. gondii antibodies were detected by means of the indirect fluorescence antibody test (IFAT ≥ 64). The highest occurrence was detected in the ...
In this study, a loop-mediated isothermal amplification (LAMP) assay was established to detect Toxoplasma gondii DNA in mice infected with T. gondii PRU strain. This LAMP assay was based on the sequence of highly repetitive B1 gene. The detect...
A simple, quick and reproducible method consisting of density-gradient centrifugation of homogenized infected mouse brain tissue on Percoll is described for the isolation and purification of cysts of Isospora (Toxoplasma) gondii. A 100% recovery of cysts, with 74.2% in a single fraction with a speci …
Infants born to mothers who have seroconverted for toxoplasmosis during being pregnant are at threat of sequelae. of 0.04 (optical denseness value), the specificity and sensitivity from the test were 67.9% and 80.3%, respectively, and the likelihood of devoid of a congenital infection when the check on oral fluid was negative was 99%. Although the performance of the test needs to be improved, oral fluid sampling appears to be a promising tool for monitoring infants with suspected congenital toxoplasmosis. INTRODUCTION is a worldwide obligate intracellular protozoan parasite that causes toxoplasmosis, which usually occurs without symptoms. However, serious manifestations may occur in immunocompromised Bmp7 patients or in fetuses. The clinical presentation of congenital infection ranges from fetal loss to severe neurologic or ocular lesions to subclinical infection (1), from which infants can develop retinal diseases during childhood or adolescence (2). In France, due to prenatal mass screening ...
A Toxoplasma gondii seroprevalence survey was conducted in poultry flocks kept under different housing systems in Israel. The seroprevalence rates were 35.4 % (46/130) in battery-raised chicken egg-layers from Jerusalem which were first raised on the ground, 12.5 % (19/152) in free-range chickens from various locations of the country and 9 % (4/45) in turkeys from the north. However, all broilers (50) and chicken breeding stock (58) kept under high biosecurity conditions in Jerusalem were found to be T. gondii seronegative. It is concluded that high biosecurity conditions prevent contamination with oocysts by rendering premises inaccessible to cats ...
Background. Well-documented outbreaks of human toxoplasmosis infection are infrequently reported. Here, we describe a community outbreak of multivisceral toxoplasmosis that occurred in Patam, a Surinamese village near the French Guianan border.. Methods. From the end of December 2003 through the middle of January 2004, 5 adult patients in Patam, including 2 pregnant women, were initially hospitalized for multivisceral toxoplasmosis. A French-Surinamese epidemiological investigation was conducted in the village; inquiries and clinical examinations were performed, and blood and environmental samples were obtained. For all serologically confirmed cases of toxoplasmosis, molecular analysis and mouse inoculations were performed for diagnosis and genetic characterization of Toxoplasma gondii.. Results. The hospitalized patients, who did not have any immunodeficiencies, presented with an infectious disease with multivisceral involvement. Serological examination confirmed acute toxoplasmosis. One adult ...
POSTDOCTORAL POSITION Biochemistry, Microbiology, Drug development Indiana University School of Medicine POSTDOCTORAL POSITION available to investigate the efficacy and mechanism of experimental drugs to treat infection caused by the protozoan parasite Toxoplasma gondii. Related to the malaria parasite, Toxoplasma causes birth defects and life-threatening infection in immunocompromised AIDS or heart transplant patients. The successful candidate will continue the … Continue reading. ...
Carbonic anhydrase-related proteins (CARPs) have previously been described as catalytically inactive proteins closely related to α-carbonic anhydrases (α-CAs). These CARPs are found in animals (both vertebrates and invertebrates) and viruses as either independent proteins or domains of other proteins. We report here the identification of a new CARP (TgCA_RP) in the unicellular organism Toxoplasma gondii that is related to the recently described η-class CA found in Plasmodium falciparum. TgCA_RP is posttranslationally modified at its C terminus with a glycosylphosphatidylinositol anchor that is important for its localization in intracellular tachyzoites. The protein localizes throughout the rhoptry bulbs of mature tachyzoites and to the outer membrane of nascent rhoptries in dividing tachyzoites, as demonstrated by immunofluorescence and immunoelectron microscopy using specific antibodies. T. gondii mutant tachyzoites lacking TgCA_RP display a growth and invasion phenotype in vitro and have ...
Phone: 778-317-4952. Many factors, both genetic and environmental, have been blamed for increasing the risk of a diagnosis of schizophrenia. Some, such as a family history of schizophrenia, are widely accepted. Others, such as infection with Toxoplasma gondii, a parasite transmitted by soil, undercooked meat and cat feces, are still viewed with skepticism.. A new study by Gary Smith, professor of population biology and epidemiology at the University of Pennsylvanias School of Veterinary Medicine, used epidemiological modeling methods to determine the proportion of schizophrenia cases that may be attributable to T. gondii infection. The work, published in the journal Preventive Veterinary Medicine, suggests that about one-fifth of cases may involve the parasite.. Infection with Toxoplasma is very common, so, even if only a small percentage of people suffer adverse consequences, we could be talking about problems that affect thousands and thousands of people, Smith said.. In the United States, ...
Silva, N. M. da, Manzan, R. M., Carneiro, W. P., Milanezi, C. M., Silva, J. S. da, Ferro, E. A. V., & Mineo, J. R. (2010). Toxoplasma gondii: the severity of toxoplasmic encephalitis in C57BL/6 mice is associated with increased ALCAM and VCAM-1 expression in the central nervous system and higher blood-brain barrier permeability. Experimental Parasitology, 126( 2), 167-177. doi:10.1016/j.exppara.2010.04. ...
Toxoplasma gondii infection is a common congenital disease in humans and domestic animals. Congenital toxoplasmosis is one of the principal causes of abortion, foetal death, and stillbirths in sheep, goats and pigs (Dubey & Beattie 1988). Severe cases occur with greater frequency when the mother is infected during the first two trimesters of pregnancy. When acquired later, symptoms tend to be subclinical or even lacking in the foetus (Desmonts & Couvreur 1974).. Numerous animal models, including primates, rabbits, guinea pigs, hamsters, mice and rats, have been used in recent years to study the pathology of the infection and the efficacy of vaccines and new drugs for the treatment of congenital transmission, chorioretinitis and toxoplasmic encephalitis. Of these, mice have been found to be the most susceptible toT. gondii and are particularly interesting model to study congenital infection.. Roberts and Alexander (1992) demonstrated that vertical Toxoplasma transmission only occurs in Balb/c ...
This report provides an overview of the impact of feral cats Felis catus on native fauna of the Pacific region, with particular reference to Australia and its island territories. In Australia, cats take a wide variety of native species of mammals, birds and reptiles, but show evident preference for young rabbits or small marsupials where these are available. Reptiles are taken primarily in and habitats, while birds often feature predominantly in the diet of cats on islands. Despite their catholic diet, population-level impacts of feral cats on native fauna have been poorly documented. There is considerable potential for competition to occur between cats and carnivorous species such as quolls and raptors, but no critical evidence has yet been adduced. There is also potential for amerisal impacts to occur, either via transmission of the pseudophyllidean tapeworm Spirometra erinacei or of the protozoan parasite Toxoplasma gondii, but evidence for deleterious effects in freeliving animals is not ...
Mice infected with LP-BM5 murine leukemia viruses develop a syndrome, termed mouse AIDS (MAIDS), characterized by increasingly severe immunodeficiency and progressive lymphoproliferation. Virus-infected mice were examined for the ability to resist acute infection and to control chronic infection with the protozoan Toxoplasma gondii, a major opportunistic pathogen of individuals infected with human immunodeficiency virus. Mice infected with the retroviruses for 2 or 4 weeks responded normally to challenge with the parasite, but mice inoculated with the protozoan 8 or 12 weeks after viral infection died with acute disease due to T. gondii. Increased sensitivity to acute infection was associated with a reduced ability to produce gamma interferon (IFN-gamma) and with established changes in CD4+ T-cell function. Mice latently infected with T. gondii and then inoculated with the retrovirus mixture were found to reactivate the parasite infection, with 30 to 40% of dually infected animals dying between ...
Toxoplasmosis is caused by the parasite Toxoplasma gondii. The infection can cause serious health problems in people with compromised immune systems. Women who become infected just before or during pregnancy may pass the parasite on to their unborn child, resulting in miscarriage, stillbirth, or an abnormally small or large head. Infection can also lead to vision loss, mental disability, seizures or other health problems later in life for the child.. Cats are most often associated with the parasite, but many other species of animals and birds also serve as hosts. The parasite also is found in people worldwide. Common symptoms of toxoplasmosis include swollen lymph nodes and flu-like symptoms.. Toxoplasmosis is considered to be a leading cause of death attributed to foodborne illness, according to the Centers for Disease Control and Prevention. More than 60 million people in the United States may be infected with Toxoplasma gondii. The parasite may be transmitted to people when they eat raw, ...
Environmental cues heavily influence the regulated programmed state of Toxoplasma that dictates the parasites life stage (54-58). The bradyzoite-stage cyst structure maintains chronic infection (59) and presents a therapeutic barrier for cyst clearance (60). Our study tracked the location(s) of IVN-associated GRA1, GRA2, GRA4, GRA6, GRA9, and GRA12 from differentiation of the PV to the mature 10-day-old in vitro cyst. Our findings confirm a recent proteomic study of the cyst wall that identified IVN-associated GRA2, GRA4, GRA9, and GRA12 in the cyst wall of in vitro cysts matured for 8 days (29). Notably, this proteomic study did not identify GRA1 or GRA6 in the cyst wall. However, GRA1 and GRA6 have been previously localized to the cyst wall via cryo-immunolabeling (19) or gold particle immunoelectron microscopy (2), respectively. The membrane tubules of the ICN present in the cyst matrix and in the cyst wall resemble tachyzoite-stage IVN membranes (18, 19), and the IVN membranes of the ...
Along the length of the conoid fibers, tubulin molecules are spaced 4 nm apart, just as in microtubules. It seems probable that conoid protofilaments exhibit parallel, as opposed to antiparallel, orientation (implying that the fiber as a whole is a polar structure) as has been observed in all naturally occurring tubulin polymers, but the signal-to-noise ratio in images of conoid fibers obtained to date is too low to confirm this supposition. However, the lack of circular symmetry in cross-section means that the lateral association of protofilaments in conoid fibers must be quite different from microtubules. The noncircular cross-sectional profile implies that the bonds between adjacent protofilaments are very different at one end of the comma compared to the other: adjacent protofilaments at the curved end must be rotated by ∼30° with respect to each other (similar to the 360/13 = 27.7 degrees in a canonical 13 protofilament microtubule), whereas adjacent protofilaments at the tail of the ...
Many intracellular pathogens subvert host membrane trafficking pathways to promote their replication. Toxoplasma multiplies in a membrane-bound parasitophorous vacuole (PV) that interacts with mammalian host organelles and intercepts Golgi Rab vesicles to acquire sphingolipids. The mechanisms of host vesicle internalization and processing within the PV remain undefined. We demonstrate that Toxoplasma sequesters a broad range of Rab vesicles into the PV. Correlative light and electron microscopy analysis of infected cells illustrates that intravacuolar Rab1A vesicles are surrounded by the PV membrane, suggesting a phagocytic-like process for vesicle engulfment. Rab11A vesicles concentrate to an intravacuolar network (IVN), but this is reduced in Δgra2 and Δgra2Δgra6 parasites, suggesting that tubules stabilized by the TgGRA2 and TgGRA6 proteins secreted by the parasite within the PV contribute to host vesicle sequestration. Overexpression of a phospholipase TgLCAT, which is localized to the ...
A case of Toxoplasma encephalitis is described in a patient who had received much immunosuppressive therapy for Hodgkins disease. Such cases have been reported in immune suppressed patients outside the United Kingdom, but a search of the literature has not revealed any previous reports from this country. Since Toxoplasma gondii is a frequent pathogen and states of immune suppression are becoming more common, further cases, can be expected. Recognition of the clinical and pathological features is important because the condition can be treated.. ...
Toxoplasma gondii causes the foremost widespread protozoan infection with a broad variety of host range. Toxoplasmosis in Immunocompetent person is usually asymptomatic but severe complications might occur in immunocompromised persons and life threatening congenital infections can develop during pregnancy. This study was conducted to investigate the prevalence and risk factors of T. gondii among healthy populations in Erbil City. A total of 167 healthy participants were examined for the detection of T. gondii in Erbil City from November 2017 to January 2018 by using Latex agglutination test and ELFA-IgM and IgG. For collecting full information about the participants, a special questionnaire sheet was prepared and data were analyzed using SPSS software version 21. Out of 167 samples examined 41(24.6%) were positive by LAT, 14(8.4%) were positive for IgG by Mini-Vidas and 26(15.6%) were positive for IgM by Mini-Vidas. The prevalence rate of toxoplasmosis among females was (25.6%) which was higher ...
New drugs are urgently needed to treat infections caused by apicomplexan parasites, such as Toxoplasma and Plasmodium. These parasites have complex life cycles that involve stages of latency and replication. In the case of Toxoplasma, latent bradyzoite tissue cysts thwart efforts to fully eradicate the infection from patients. An ideal drug should not only be effective against the proliferative stage of the parasite but also exert dual activity against the tissue cyst stage. We previously showed that translational control via the phosphorylation of TgIF2α is critical during both the tachyzoite and bradyzoite stages and is also important in various aspects of Plasmodium physiology (9, 10, 26, 27). These findings suggest that pharmacological interference in translational control through parasite eIF2α may serve as a broad-spectrum strategy that targets multiple life cycle stages of different pathogens.. Two established inhibitors of TgIF2α dephosphorylation, guanabenz and salubrinal, have been ...
A monolayer of human foreskin fibroblast cells was infected with Toxoplasma gondii expressing YFP-tagged Tgalpha1tubulin and mRFP-tagged TgDLC (dynein...
A monolayer of human foreskin fibroblast cells was infected with Toxoplasma gondii expressing YFP-tagged TgIMC1 (innermembrane complex scaffold protei...
Objective. The aim of the survey was to evaluate Toxoplasma gondii seroprevalence in small ruminants and possible risk factors associated with the infection. Materials and methods. Sera from 474 goats and 502 sheep reared on 42 farms in northern Italy were collected and tested for IgG antibodies to T. gondii by IFAT (indirect immunofluorescence antibody test). To identify risk factors, a binary logistic regression analysis of the variables was performed. An audit form about farm management was used. Results. Antibodies to T. gondii were found in 96.6% of goat farms and in 87.5% of sheep farms; 41.7% goats and 59.3% sheep resulted positive. Seroprevalence was significantly higher in sheep than in goats. Seroprevalence values were similar in goats from eastern and western areas, whereas goats from the southern area were at lower risk of infection. Saanen goats presented the lowest seroprevalence (30.7 %), whereas cross-breed exhibited the highest rate (48.7%). Goats from farms housing both sheep ...
Mast Group Ltd. provides a range of simple and rapid latex agglutination kits for Staphylococcus aureus, Methicillin resistant Staphylococcus aureus, Streptococcal grouping, Toxoplasma and Rheumatoid Factor.The kits utilise highly specific antibodies suitable for clinical and veterinary diagnostic use, all reagents within each kit are supplied for convenience and results are easy to read with toxoplasma igg igm rapid test kit veterinary ...
The analysis of 4450 toxoplasma serology results showed that 59 (1.3%) latex agglutination reactions were not confirmed in the dye test. These discrepant results were associated with an unspecified IgM antibody but not associated with kit batch variation, inactivation of sera, concurrent cytomegalovirus infection, or the presence of hepatitis B virus e antigen. The latex agglutination test is useful as a screen for toxoplasma infection but false positive reactions do occur. Patients at risk of severe toxoplasmosis should be investigated by additional tests.. ...