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Sample records for intracellular pathogen toxoplasma

  1. Pathogenic mechanisms of intracellular bacteria.

    Science.gov (United States)

    Niller, Hans Helmut; Masa, Roland; Venkei, Annamária; Mészáros, Sándor; Minarovits, Janos

    2017-06-01

    We wished to overview recent data on a subset of epigenetic changes elicited by intracellular bacteria in human cells. Reprogramming the gene expression pattern of various host cells may facilitate bacterial growth, survival, and spread. DNA-(cytosine C5)-methyltransferases of Mycoplasma hyorhinis targeting cytosine-phosphate-guanine (CpG) dinucleotides and a Mycobacterium tuberculosis methyltransferase targeting non-CpG sites methylated the host cell DNA and altered the pattern of gene expression. Gene silencing by CpG methylation and histone deacetylation, mediated by cellular enzymes, also occurred in M. tuberculosis-infected macrophages. M. tuberculosis elicited cell type-specific epigenetic changes: it caused increased DNA methylation in macrophages, but induced demethylation, deposition of euchromatic histone marks and activation of immune-related genes in dendritic cells. A secreted transposase of Acinetobacter baumannii silenced a cellular gene, whereas Mycobacterium leprae altered the epigenotype, phenotype, and fate of infected Schwann cells. The 'keystone pathogen' oral bacterium Porphyromonas gingivalis induced local DNA methylation and increased the level of histone acetylation in host cells. These epigenetic changes at the biofilm-gingiva interface may contribute to the development of periodontitis. Epigenetic regulators produced by intracellular bacteria alter the epigenotype and gene expression pattern of host cells and play an important role in pathogenesis.

  2. Autophagic clearance of bacterial pathogens: molecular recognition of intracellular microorganisms.

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    Pareja, Maria Eugenia Mansilla; Colombo, Maria I

    2013-01-01

    Autophagy is involved in several physiological and pathological processes. One of the key roles of the autophagic pathway is to participate in the first line of defense against the invasion of pathogens, as part of the innate immune response. Targeting of intracellular bacteria by the autophagic machinery, either in the cytoplasm or within vacuolar compartments, helps to control bacterial proliferation in the host cell, controlling also the spreading of the infection. In this review we will describe the means used by diverse bacterial pathogens to survive intracellularly and how they are recognized by the autophagic molecular machinery, as well as the mechanisms used to avoid autophagic clearance.

  3. Toxoplasma

    Science.gov (United States)

    T. gondii is an obligate intracellular protozoan parasite that can infect all warm blooded animals ranging from: humans, pets, livestock, to marine aquatic animals. The definitive host is the feline species (both domestic and wild cats), where the sexual stage of the life cycle o...

  4. Advances in genetic manipulation of obligate intracellular bacterial pathogens

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    Paul eBeare

    2011-05-01

    Full Text Available Infections by obligate intracellular bacterial pathogens result in significant morbidity and mortality worldwide. These bacteria include Chlamydia spp., which causes millions of cases of sexually transmitted disease and blinding trachoma annually, and members of the α-proteobacterial genera Anaplasma, Ehrlichia, Orientia and Rickettsia, agents of serious human illnesses including epidemic typhus. Coxiella burnetii, the agent of human Q fever, has also been considered a prototypical obligate intracellular bacterium, but recent host cell-free (axenic growth has rescued it from obligatism. The historic genetic intractability of obligate intracellular bacteria has severely limited molecular dissection of their unique lifestyles and virulence factors involved in pathogenesis. Host cell restricted growth is a significant barrier to genetic transformation that can make simple procedures for free-living bacteria, such as cloning, exceedingly difficult. Low transformation efficiency requiring long term culture in host cells to expand small transformant populations is another obstacle. Despite numerous technical limitations, the last decade has witnessed significant gains in genetic manipulation of obligate intracellular bacteria including allelic exchange. Continued development of genetic tools should soon enable routine mutation and complementation strategies for virulence factor discovery and stimulate renewed interest in these refractory pathogens. In this review, we discuss the technical challenges associated with genetic transformation of obligate intracellular bacteria and highlight advances made with individual genera.

  5. A Toxoplasma gondii protein with homology to intracellular type Na+/H+ exchangers is important for osmoregulation and invasion

    International Nuclear Information System (INIS)

    Francia, Maria E.; Wicher, Sarah; Pace, Douglas A.; Sullivan, Jack; Moreno, Silvia N.J.; Arrizabalaga, Gustavo

    2011-01-01

    The obligate intracellular parasite Toxoplasma gondii is exposed to a variety of physiological conditions while propagating in an infected organism. The mechanisms by which Toxoplasma overcomes these dramatic changes in its environment are not known. In yeast and plants, ion detoxification and osmotic regulation are controlled by vacuolar compartments. A novel compartment named the plant-like vacuole or vacuolar compartment (PLV/VAC) has recently been described in T.gondii, which could potentially protect extracellular tachyzoites against salt and other ionic stresses. Here, we report the molecular characterization of the vacuolar type Na + /H + exchanger in T. gondii, TgNHE3, and its co-localization with the PLV/VAC proton-pyrophosphatase (TgVP1). We have created a TgNHE3 knockout strain, which is more sensitive to hyperosmotic shock and toxic levels of sodium, possesses a higher intracellular Ca 2+ concentration [Ca 2+ ] i , and exhibits a reduced host invasion efficiency. The defect in invasion correlates with a measurable reduction in the secretion of the adhesin TgMIC2. Overall, our results suggest that the PLV/VAC has functions analogous to those of the vacuolar compartments of plants and yeasts, providing the parasite with a mechanism to resist ionic fluctuations and, potentially, regulate protein trafficking.

  6. The Chlamydia psittaci genome: a comparative analysis of intracellular pathogens.

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    Voigt, Anja; Schöfl, Gerhard; Saluz, Hans Peter

    2012-01-01

    Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis. A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins. This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions.

  7. The Chlamydia psittaci genome: a comparative analysis of intracellular pathogens.

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    Anja Voigt

    Full Text Available Chlamydiaceae are a family of obligate intracellular pathogens causing a wide range of diseases in animals and humans, and facing unique evolutionary constraints not encountered by free-living prokaryotes. To investigate genomic aspects of infection, virulence and host preference we have sequenced Chlamydia psittaci, the pathogenic agent of ornithosis.A comparison of the genome of the avian Chlamydia psittaci isolate 6BC with the genomes of other chlamydial species, C. trachomatis, C. muridarum, C. pneumoniae, C. abortus, C. felis and C. caviae, revealed a high level of sequence conservation and synteny across taxa, with the major exception of the human pathogen C. trachomatis. Important differences manifest in the polymorphic membrane protein family specific for the Chlamydiae and in the highly variable chlamydial plasticity zone. We identified a number of psittaci-specific polymorphic membrane proteins of the G family that may be related to differences in host-range and/or virulence as compared to closely related Chlamydiaceae. We calculated non-synonymous to synonymous substitution rate ratios for pairs of orthologous genes to identify putative targets of adaptive evolution and predicted type III secreted effector proteins.This study is the first detailed analysis of the Chlamydia psittaci genome sequence. It provides insights in the genome architecture of C. psittaci and proposes a number of novel candidate genes mostly of yet unknown function that may be important for pathogen-host interactions.

  8. Characteristic features of intracellular pathogenic Leptospira in infected murine macrophages.

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    Toma, Claudia; Okura, Nobuhiko; Takayama, Chitoshi; Suzuki, Toshihiko

    2011-11-01

    Leptospira interrogans is a spirochaete responsible for a zoonotic disease known as leptospirosis. Leptospires are able to penetrate the abraded skin and mucous membranes and rapidly disseminate to target organs such as the liver, lungs and kidneys. How this pathogen escape from innate immune cells and spread to target organs remains poorly understood. In this paper, the intracellular trafficking undertaken by non-pathogenic Leptospira biflexa and pathogenic L. interrogans in mouse bone marrow-derived macrophages was compared. The delayed in the clearance of L. interrogans was observed. Furthermore, the acquisition of lysosomal markers by L. interrogans-containing phagosomes lagged behind that of L. biflexa-containing phagosomes, and although bone marrow-derived macrophages could degrade L. biflexa as well as L. interrogans, a population of L. interrogans was able to survive and replicate. Intact leptospires were found within vacuoles at 24 h post infection, suggesting that bacterial replication occurs within a membrane-bound compartment. In contrast, L. biflexa were completely degraded at 24 h post infection. Furthermore, L. interrogans but not L. biflexa, were released to the extracellular milieu. These results suggest that pathogenic leptospires are able to survive, replicate and exit from mouse macrophages, enabling their eventual spread to target organs. © 2011 Blackwell Publishing Ltd.

  9. Metabolic Cooperation of Glucose and Glutamine Is Essential for the Lytic Cycle of Obligate Intracellular Parasite Toxoplasma gondii.

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    Nitzsche, Richard; Zagoriy, Vyacheslav; Lucius, Richard; Gupta, Nishith

    2016-01-01

    Toxoplasma gondii is a widespread protozoan parasite infecting nearly all warm-blooded organisms. Asexual reproduction of the parasite within its host cells is achieved by consecutive lytic cycles, which necessitates biogenesis of significant energy and biomass. Here we show that glucose and glutamine are the two major physiologically important nutrients used for the synthesis of macromolecules (ATP, nucleic acid, proteins, and lipids) in T. gondii, and either of them is sufficient to ensure the parasite survival. The parasite can counteract genetic ablation of its glucose transporter by increasing the flux of glutamine-derived carbon through the tricarboxylic acid cycle and by concurrently activating gluconeogenesis, which guarantee a continued biogenesis of ATP and biomass for host-cell invasion and parasite replication, respectively. In accord, a pharmacological inhibition of glutaminolysis or oxidative phosphorylation arrests the lytic cycle of the glycolysis-deficient mutant, which is primarily a consequence of impaired invasion due to depletion of ATP. Unexpectedly, however, intracellular parasites continue to proliferate, albeit slower, notwithstanding a simultaneous deprivation of glucose and glutamine. A growth defect in the glycolysis-impaired mutant is caused by a compromised synthesis of lipids, which cannot be counterbalanced by glutamine but can be restored by acetate. Consistently, supplementation of parasite cultures with exogenous acetate can amend the lytic cycle of the glucose transport mutant. Such plasticity in the parasite's carbon flux enables a growth-and-survival trade-off in assorted nutrient milieus, which may underlie the promiscuous survival of T. gondii tachyzoites in diverse host cells. Our results also indicate a convergence of parasite metabolism with cancer cells. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  10. Metabolic Cooperation of Glucose and Glutamine Is Essential for the Lytic Cycle of Obligate Intracellular Parasite Toxoplasma gondii*

    Science.gov (United States)

    Nitzsche, Richard; Zagoriy, Vyacheslav; Lucius, Richard; Gupta, Nishith

    2016-01-01

    Toxoplasma gondii is a widespread protozoan parasite infecting nearly all warm-blooded organisms. Asexual reproduction of the parasite within its host cells is achieved by consecutive lytic cycles, which necessitates biogenesis of significant energy and biomass. Here we show that glucose and glutamine are the two major physiologically important nutrients used for the synthesis of macromolecules (ATP, nucleic acid, proteins, and lipids) in T. gondii, and either of them is sufficient to ensure the parasite survival. The parasite can counteract genetic ablation of its glucose transporter by increasing the flux of glutamine-derived carbon through the tricarboxylic acid cycle and by concurrently activating gluconeogenesis, which guarantee a continued biogenesis of ATP and biomass for host-cell invasion and parasite replication, respectively. In accord, a pharmacological inhibition of glutaminolysis or oxidative phosphorylation arrests the lytic cycle of the glycolysis-deficient mutant, which is primarily a consequence of impaired invasion due to depletion of ATP. Unexpectedly, however, intracellular parasites continue to proliferate, albeit slower, notwithstanding a simultaneous deprivation of glucose and glutamine. A growth defect in the glycolysis-impaired mutant is caused by a compromised synthesis of lipids, which cannot be counterbalanced by glutamine but can be restored by acetate. Consistently, supplementation of parasite cultures with exogenous acetate can amend the lytic cycle of the glucose transport mutant. Such plasticity in the parasite's carbon flux enables a growth-and-survival trade-off in assorted nutrient milieus, which may underlie the promiscuous survival of T. gondii tachyzoites in diverse host cells. Our results also indicate a convergence of parasite metabolism with cancer cells. PMID:26518878

  11. Modeling the intracellular pathogen-immune interaction with cure rate

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    Dubey, Balram; Dubey, Preeti; Dubey, Uma S.

    2016-09-01

    Many common and emergent infectious diseases like Influenza, SARS, Hepatitis, Ebola etc. are caused by viral pathogens. These infections can be controlled or prevented by understanding the dynamics of pathogen-immune interaction in vivo. In this paper, interaction of pathogens with uninfected and infected cells in presence or absence of immune response are considered in four different cases. In the first case, the model considers the saturated nonlinear infection rate and linear cure rate without absorption of pathogens into uninfected cells and without immune response. The next model considers the effect of absorption of pathogens into uninfected cells while all other terms are same as in the first case. The third model incorporates innate immune response, humoral immune response and Cytotoxic T lymphocytes (CTL) mediated immune response with cure rate and without absorption of pathogens into uninfected cells. The last model is an extension of the third model in which the effect of absorption of pathogens into uninfected cells has been considered. Positivity and boundedness of solutions are established to ensure the well-posedness of the problem. It has been found that all the four models have two equilibria, namely, pathogen-free equilibrium point and pathogen-present equilibrium point. In each case, stability analysis of each equilibrium point is investigated. Pathogen-free equilibrium is globally asymptotically stable when basic reproduction number is less or equal to unity. This implies that control or prevention of infection is independent of initial concentration of uninfected cells, infected cells, pathogens and immune responses in the body. The proposed models show that introduction of immune response and cure rate strongly affects the stability behavior of the system. Further, on computing basic reproduction number, it has been found to be minimum for the fourth model vis-a-vis other models. The analytical findings of each model have been exemplified by

  12. Intracellular phase for an extracellular bacterial pathogen: MgtC shows the way

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    Audrey Bernut

    2015-08-01

    Full Text Available Pseudomonas aeruginosa is an extracellular pathogen known to impair host phagocytic functions. However, our recent results identify MgtC as a novel actor in P. aeruginosa virulence, which plays a role in an intramacrophage phase of this pathogen. In agreement with its intracellular function, P. aeruginosa mgtC gene expression is strongly induced when the bacteria reside within macrophages. MgtC was previously known as a horizontally-acquired virulence factor important for multiplication inside macrophages in several intracellular bacterial pathogens. MgtC thus provides a singular example of a virulence determinant that subverts macrophages both in intracellular and extracellular pathogens. Moreover, we demonstrate that P. aeru-ginosa MgtC is required for optimal growth in Mg2+ deprived medium, a property shared by MgtC factors from intracellular pathogens and, under Mg2+ limitation, P. aeruginosaMgtC prevents biofilm formation. We propose that MgtC has a similar function in intracellular and extracellular pathogens, which contributes to macrophage resistance and fine-tune adaptation to the host in relation to the different bacterial lifestyles. MgtC thus appears as an attractive target for antivirulence strategies and our work provides a natural peptide as MgtC antagonist, which paves the way for the development of MgtC inhibitors.

  13. Effects of ionizing radiation over the structure, metabolism and infectivity of a pathogenic protozoan, Toxoplasma gondii

    International Nuclear Information System (INIS)

    Hiramoto, Roberto Mitsuyoshi

    1998-01-01

    The intracellular parasite Toxoplasma gondii (Apicomplexa), has as definitive host domestic and wild felines and as intermediate hosts most species of mammals and birds, Including man. The infection in man is usually asymptomatic, but can become a severe and lethal illness in some special groups like the fetus of primoinfected pregnant woman, or in AIDS and transplanted patients. The transmission is due to ingestion of food or water contaminated with oocysts from cat feces as well as raw or rare cooked cyst containing meet. There is no available vaccine against toxoplasmosis, with some reports of the use ionizing radiation in order to attenuate or suppress the parasite. These studies are promising, but more research is needed to optimize the radiation process and to clarify those alterations caused on T gondii.Using a increasing doses of 60 Co irradiation on T.gondii tachyzoites, we studied many parameters such as morphology, both at optical and electron microscopy level, detection of DNA fragmentation, metabolism alterations (cellular oxidative burst, protein, nucleic acids and DNA synthesis), determination of the parasite survival both in in vivo and in vitro models, antigenicity and immunogenicity after the process, cellular invasion and irradiated tachyzoite induced protection. After definition of 200 Gy of 60 Co irradiation as the lower radiation dose that suppress parasite growth in vitro and in vivo, we found no detectable changes in parasite viability, its cell invasion capacity or in its structural proteins. DNA fragmentation like apoptosis or alterations of the parasite metabolism were similarly not affected by radiation. Mice infection with irradiated parasites induce partial protection when these animals were re-inoculated with non irradiated virulent parasites, inducing greater specific IgG levels as well as a longer survival. Irradiated T.gondii maintains its the ability of invasion, even under radiation effects. Based on our results we conclude that

  14. Directed antigen delivery as a vaccine strategy for an intracellular bacterial pathogen

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    Bouwer, H. G. Archie; Alberti-Segui, Christine; Montfort, Megan J.; Berkowitz, Nathan D.; Higgins, Darren E.

    2006-03-01

    We have developed a vaccine strategy for generating an attenuated strain of an intracellular bacterial pathogen that, after uptake by professional antigen-presenting cells, does not replicate intracellularly and is readily killed. However, after degradation of the vaccine strain within the phagolysosome, target antigens are released into the cytosol for endogenous processing and presentation for stimulation of CD8+ effector T cells. Applying this strategy to the model intracellular pathogen Listeria monocytogenes, we show that an intracellular replication-deficient vaccine strain is cleared rapidly in normal and immunocompromised animals, yet antigen-specific CD8+ effector T cells are stimulated after immunization. Furthermore, animals immunized with the intracellular replication-deficient vaccine strain are resistant to lethal challenge with a virulent WT strain of L. monocytogenes. These studies suggest a general strategy for developing safe and effective, attenuated intracellular replication-deficient vaccine strains for stimulation of protective immune responses against intracellular bacterial pathogens. CD8+ T cell | replication-deficient | Listeria monocytogenes

  15. Cytosolic Access of Intracellular Bacterial Pathogens: The Shigella Paradigm.

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    Mellouk, Nora; Enninga, Jost

    2016-01-01

    Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  16. Cytosolic access of intracellular bacterial pathogens: the Shigella paradigm

    Directory of Open Access Journals (Sweden)

    Nora eMellouk

    2016-04-01

    Full Text Available Shigella is a Gram-negative bacterial pathogen, which causes bacillary dysentery in humans. A crucial step of Shigella infection is its invasion of epithelial cells. Using a type III secretion system, Shigella injects several bacterial effectors ultimately leading to bacterial internalization within a vacuole. Then, Shigella escapes rapidly from the vacuole, it replicates within the cytosol and spreads from cell-to-cell. The molecular mechanism of vacuolar rupture used by Shigella has been studied in some detail during the recent years and new paradigms are emerging about the underlying molecular events. For decades, bacterial effector proteins were portrayed as main actors inducing vacuolar rupture. This includes the effector/translocators IpaB and IpaC. More recently, this has been challenged and an implication of the host cell in the process of vacuolar rupture has been put forward. This includes the bacterial subversion of host trafficking regulators, such as the Rab GTPase Rab11. The involvement of the host in determining bacterial vacuolar integrity has also been found for other bacterial pathogens, particularly for Salmonella. Here, we will discuss our current view of host factor and pathogen effector implications during Shigella vacuolar rupture and the steps leading to it.

  17. Post-translational Control of Intracellular Pathogen Sensing Pathways.

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    Chiang, Cindy; Gack, Michaela U

    2017-01-01

    Mammalian cells recognize virus-derived nucleic acids using a defined set of intracellular sensors including the DNA sensors cyclic GMP-AMP (cGAMP) synthase (cGAS) and interferon gamma (IFNγ)-inducible protein 16 (IFI16) as well as viral RNA receptors of the retinoic acid-inducible gene I (RIG-I)-like receptor (RLR) family. Following innate immune recognition, these sensors launch an immune response that is characterized by the transcriptional upregulation of many antiviral molecules, including proinflammatory cytokines, chemokines, and IFN-stimulated genes. Recent studies have demonstrated that the signal transduction initiated by these sensors is sophisticatedly regulated by post-translational modifications (PTMs) resulting in a robust yet 'tunable' cytokine response to maintain immune homeostasis. Here we summarize recent advances in our understanding of how PTMs and regulatory enzymes control the signaling activity of RLRs, cGAS, and IFI16 as well as their proximal adaptor proteins. Copyright © 2016 Elsevier Ltd. All rights reserved.

  18. Metabolic Cooperation of Glucose and Glutamine Is Essential for the Lytic Cycle of Obligate Intracellular Parasite Toxoplasma gondii*

    OpenAIRE

    Nitzsche, Richard; Zagoriy, Vyacheslav; Lucius, Richard; Gupta, Nishith

    2015-01-01

    Toxoplasma gondii is a widespread protozoan parasite infecting nearly all warm-blooded organisms. Asexual reproduction of the parasite within its host cells is achieved by consecutive lytic cycles, which necessitates biogenesis of significant energy and biomass. Here we show that glucose and glutamine are the two major physiologically important nutrients used for the synthesis of macromolecules (ATP, nucleic acid, proteins, and lipids) in T. gondii, and either of them is sufficient to ensure ...

  19. Toxoplasma gondii seropositivity and co-infection with TORCH pathogens in high-risk patients from Qatar.

    Science.gov (United States)

    Abu-Madi, Marawan A; Behnke, Jerzy M; Dabritz, Haydee A

    2010-04-01

    Testing of patients who are deemed to be at high risk for TORCH pathogens, e.g., pregnant women, their fetuses, neonates, and acquired immunodeficiency syndrome (AIDS) patients, is important so that specific treatment can be initiated. This study included 1,857 such patients between 2005 and 2008. Logistic regression was used to evaluate factors associated with Toxoplasma gondii seropositivity. Among 823 women of childbearing age, 35.1% and 5.2% tested positive for T. gondii IgG and IgM, respectively. Three infants nationality, positive cytomegalovirus (CMV) and herpes simplex virus (HSV)-1 serostatus, and negative rubella IgG results. The decreasing prevalence of IgM antibodies between 2005 and 2008 suggested that exposure to T. gondii from food or environmental sources declined over this period in Qatar. Population-based studies of newborns would be helpful to accurately estimate incidence of congenital toxoplasmosis.

  20. Type IV pili in Francisella – A virulence trait in an intracellular pathogen

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    Emelie eNäslund Salomonsson

    2011-02-01

    Full Text Available Francisella tularensis is a highly virulent intracellular human pathogen that is capable of rapid proliferation in the infected host. Mutants affected in intracellular survival and growth are highly attenuated which highlights the importance of the intracellular phase of the infection. Genomic analysis has revealed that Francisella encodes all genes required for expression of functional type IV pili (Tfp, and in this focused review we summarise recent findings regarding this system in the pathogenesis of tularemia. Tfp are dynamic adhesive structures that have been identified as major virulence determinants in several human pathogens, but it is not obvious what role these structures could have in an intracellular pathogen like Francisella. In the human pathogenic strains, genes required for secretion and assembly of Tfp and one pilin, PilA, have shown to be required for full virulence. Importantly, specific genetic differences have been identified between the different Francisella subspecies where in the most pathogenic type A variants all genes are intact while several Tfp genes are pseudogenes in the less pathogenic type B strains. This suggests that there has been a selection for expression of Tfp with different properties in the different subspecies. There is also a possibility that the genetic differences reflect adaption to different environmental niches of the subspecies and plays a role in transmission of tularemia. This is also in line with recent findings where Tfp pilins are found to be glycosylated which could reflect a role for Tfp in the environment to promote survival and transmission. We are still far from understanding the role of Tfp in virulence and transmission of tularemia, but with the genomic information and genetic tools available we are in a good position to address these issues in the future.

  1. Anti-parasitic action and elimination of intracellular Toxoplasma gondii in the presence of novel thiosemicarbazone and its 4-thiazolidinone derivatives

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    C.S. Carvalho

    2010-02-01

    Full Text Available Toxoplasma, which infects all eukaryotic cells, is considered to be a good system for the study of drug action and of the behavior of infected host cells. In the present study, we asked if thiosemicarbazone derivatives can be effective against tachyzoites and which morphological and ultrastructural features of host cells and parasites are associated with the destruction of Toxoplasma. The compounds were tested in infected Vero cell culture using concentration screens (0.1 to 20 mM. The final concentration of 1 mM was chosen for biological assay. The following results were obtained: 1 These new derivatives decreased T. gondii infection with an in vitro parasite IC50% of 0.2-0.7 mM, without a significant effect on host cells and the more efficient compounds were 2, 3 (thiosemicarbazone derivatives and 4 (thiazolidinone derivative; 2 The main feature observed during parasite elimination was continuous morphological disorganization of the tachyzoite secretory system, progressive organelle vesiculation, and then complete disruption; 3 Ultrastructural assays also revealed that progressive vesiculation in the cytoplasm of treated parasites did not occur in the host cell; 4 Vesiculation inside the parasite resulted in death, but this feature occurred asynchronously in different intracellular tachyzoites; 5 The death and elimination of T. gondii was associated with features such as apoptosis-like stage, acidification and digestion of parasites into parasitophorous vacuoles. Our results suggest that these new chemical compounds are promising for the elimination of intracellular parasites by mainly affecting tachyzoite development at 1 mM concentration for 24 h of treatment.

  2. Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders

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    C. J. Carter

    2013-01-01

    Full Text Available Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (multiple sclerosis, and autism (, but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD to 33% (MS of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as to the disease itself.

  3. ABMA, a small molecule that inhibits intracellular toxins and pathogens by interfering with late endosomal compartments.

    Science.gov (United States)

    Wu, Yu; Pons, Valérie; Goudet, Amélie; Panigai, Laetitia; Fischer, Annette; Herweg, Jo-Ana; Kali, Sabrina; Davey, Robert A; Laporte, Jérôme; Bouclier, Céline; Yousfi, Rahima; Aubenque, Céline; Merer, Goulven; Gobbo, Emilie; Lopez, Roman; Gillet, Cynthia; Cojean, Sandrine; Popoff, Michel R; Clayette, Pascal; Le Grand, Roger; Boulogne, Claire; Tordo, Noël; Lemichez, Emmanuel; Loiseau, Philippe M; Rudel, Thomas; Sauvaire, Didier; Cintrat, Jean-Christophe; Gillet, Daniel; Barbier, Julien

    2017-11-14

    Intracellular pathogenic microorganisms and toxins exploit host cell mechanisms to enter, exert their deleterious effects as well as hijack host nutrition for their development. A potential approach to treat multiple pathogen infections and that should not induce drug resistance is the use of small molecules that target host components. We identified the compound 1-adamantyl (5-bromo-2-methoxybenzyl) amine (ABMA) from a cell-based high throughput screening for its capacity to protect human cells and mice against ricin toxin without toxicity. This compound efficiently protects cells against various toxins and pathogens including viruses, intracellular bacteria and parasite. ABMA provokes Rab7-positive late endosomal compartment accumulation in mammalian cells without affecting other organelles (early endosomes, lysosomes, the Golgi apparatus, the endoplasmic reticulum or the nucleus). As the mechanism of action of ABMA is restricted to host-endosomal compartments, it reduces cell infection by pathogens that depend on this pathway to invade cells. ABMA may represent a novel class of broad-spectrum compounds with therapeutic potential against diverse severe infectious diseases.

  4. Epigenetic silencing of host cell defense genes enhances intracellular survival of the rickettsial pathogen Anaplasma phagocytophilum.

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    Jose C Garcia-Garcia

    2009-06-01

    Full Text Available Intracellular bacteria have evolved mechanisms that promote survival within hostile host environments, often resulting in functional dysregulation and disease. Using the Anaplasma phagocytophilum-infected granulocyte model, we establish a link between host chromatin modifications, defense gene transcription and intracellular bacterial infection. Infection of THP-1 cells with A. phagocytophilum led to silencing of host defense gene expression. Histone deacetylase 1 (HDAC1 expression, activity and binding to the defense gene promoters significantly increased during infection, which resulted in decreased histone H3 acetylation in infected cells. HDAC1 overexpression enhanced infection, whereas pharmacologic and siRNA HDAC1 inhibition significantly decreased bacterial load. HDAC2 does not seem to be involved, since HDAC2 silencing by siRNA had no effect on A. phagocytophilum intracellular propagation. These data indicate that HDAC up-regulation and epigenetic silencing of host cell defense genes is required for A. phagocytophilum infection. Bacterial epigenetic regulation of host cell gene transcription could be a general mechanism that enhances intracellular pathogen survival while altering cell function and promoting disease.

  5. Thioredoxin 80-Activated-Monocytes (TAMs) Inhibit the Replication of Intracellular Pathogens

    DEFF Research Database (Denmark)

    Cortes-Bratti, Ximena; Brasseres, Eugenie; Herrera-Rodriquez, Fabiola

    2011-01-01

    Background: Thioredoxin 80 (Trx80) is an 80 amino acid natural cleavage product of Trx, produced primarily by monocytes. Trx80 induces differentiation of human monocytes into a novel cell type, named Trx80-activated-monocytes (TAMs). Principal Findings: In this investigation we present evidence...... for a role of TAMs in the control of intracellular bacterial infections. As model pathogens we have chosen Listeria monocytogenes and Brucella abortus which replicate in the cytosol and the endoplasmic reticulum respectively. Our data indicate that TAMs efficiently inhibit intracellular growth of both L...... in TAMs compared to that observed in control cells 24 h post-infection, indicating that TAMs kill bacteria by preventing their escape from the endosomal compartments, which progress into a highly degradative phagolysosome. Significance: Our results show that Trx80 potentiates the bactericidal activities...

  6. Fierce competition between Toxoplasma and Chlamydia for host cell structures in dually infected cells.

    Science.gov (United States)

    Romano, Julia D; de Beaumont, Catherine; Carrasco, Jose A; Ehrenman, Karen; Bavoil, Patrik M; Coppens, Isabelle

    2013-02-01

    The prokaryote Chlamydia trachomatis and the protozoan Toxoplasma gondii, two obligate intracellular pathogens of humans, have evolved a similar modus operandi to colonize their host cell and salvage nutrients from organelles. In order to gain fundamental knowledge on the pathogenicity of these microorganisms, we have established a cell culture model whereby single fibroblasts are coinfected by C. trachomatis and T. gondii. We previously reported that the two pathogens compete for the same nutrient pools in coinfected cells and that Toxoplasma holds a significant competitive advantage over Chlamydia. Here we have expanded our coinfection studies by examining the respective abilities of Chlamydia and Toxoplasma to co-opt the host cytoskeleton and recruit organelles. We demonstrate that the two pathogen-containing vacuoles migrate independently to the host perinuclear region and rearrange the host microtubular network around each vacuole. However, Toxoplasma outcompetes Chlamydia to the host microtubule-organizing center to the detriment of the bacterium, which then shifts to a stress-induced persistent state. Solely in cells preinfected with Chlamydia, the centrosomes become associated with the chlamydial inclusion, while the Toxoplasma parasitophorous vacuole displays growth defects. Both pathogens fragment the host Golgi apparatus and recruit Golgi elements to retrieve sphingolipids. This study demonstrates that the productive infection by both Chlamydia and Toxoplasma depends on the capability of each pathogen to successfully adhere to a finely tuned developmental program that aims to remodel the host cell for the pathogen's benefit. In particular, this investigation emphasizes the essentiality of host organelle interception by intravacuolar pathogens to facilitate access to nutrients.

  7. Brucella abortus Induces a Warburg Shift in Host Metabolism That Is Linked to Enhanced Intracellular Survival of the Pathogen.

    Science.gov (United States)

    Czyż, Daniel M; Willett, Jonathan W; Crosson, Sean

    2017-08-01

    Intracellular bacterial pathogens exploit host cell resources to replicate and survive inside the host. Targeting these host systems is one promising approach to developing novel antimicrobials to treat intracellular infections. We show that human macrophage-like cells infected with Brucella abortus undergo a metabolic shift characterized by attenuated tricarboxylic acid cycle metabolism, reduced amino acid consumption, altered mitochondrial localization, and increased lactate production. This shift to an aerobic glycolytic state resembles the Warburg effect, a change in energy production that is well described in cancer cells and also occurs in activated inflammatory cells. B. abortus efficiently uses lactic acid as its sole carbon and energy source and requires the ability to metabolize lactate for normal survival in human macrophage-like cells. We demonstrate that chemical inhibitors of host glycolysis and lactate production do not affect in vitro growth of B. abortus in axenic culture but decrease its survival in the intracellular niche. Our data support a model in which infection shifts host metabolism to a Warburg-like state, and B. abortus uses this change in metabolism to promote intracellular survival. Pharmacological perturbation of these features of host cell metabolism may be a useful strategy to inhibit infection by intracellular pathogens. IMPORTANCE Brucella spp. are intracellular bacterial pathogens that cause disease in a range of mammals, including livestock. Transmission from livestock to humans is common and can lead to chronic human disease. Human macrophage-like cells infected with Brucella abortus undergo a Warburg-like metabolic shift to an aerobic glycolytic state where the host cells produce lactic acid and have reduced amino acid catabolism. We provide evidence that the pathogen can exploit this change in host metabolism to support growth and survival in the intracellular niche. Drugs that inhibit this shift in host cell metabolism

  8. Concentration and retention of Toxoplasma gondii oocysts by marine snails demonstrate a novel mechanism for transmission of terrestrial zoonotic pathogens in coastal ecosystems

    Science.gov (United States)

    Krusor, Colin; Smith, Woutrina A.; Tinker, M. Tim; Silver, Mary; Conrad, Patricia A.; Shapiro, Karen

    2015-01-01

    The parasite Toxoplasma gondii is an environmentally persistent pathogen that can cause fatal disease in humans, terrestrial warm-blooded animals and aquatic mammals. Although an association between T. gondii exposure and prey specialization on marine snails was identified in threatened California sea otters, the ability of kelp-dwelling snails to transmit terrestrially derived pathogens has not been previously investigated. The objective of this study was to measure concentration and retention of T. gondii by marine snails in laboratory aquaria, and to test for natural T. gondii contamination in field-collected snails. Following exposure to T. gondii-containing seawater, oocysts were detected by microscopy in snail faeces and tissues for 10 and 3 days respectively. Nested polymerase chain reaction was also applied as a method for confirming putative T. gondii oocysts detected in snail faeces and tissues by microscopy. Toxoplasma gondiiwas not detected in field-collected snails. Results suggest that turban snails are competent transport hosts for T. gondii. By concentrating oocysts in faecal pellets, snails may facilitate entry of T. gondii into the nearshore marine food web. This novel mechanism also represents a general pathway by which marine transmission of terrestrially derived microorganisms can be mediated via pathogen concentration and retention by benthic invertebrates.

  9. Diverse mechanisms of metaeffector activity in an intracellular bacterial pathogen, Legionella pneumophila.

    Science.gov (United States)

    Urbanus, Malene L; Quaile, Andrew T; Stogios, Peter J; Morar, Mariya; Rao, Chitong; Di Leo, Rosa; Evdokimova, Elena; Lam, Mandy; Oatway, Christina; Cuff, Marianne E; Osipiuk, Jerzy; Michalska, Karolina; Nocek, Boguslaw P; Taipale, Mikko; Savchenko, Alexei; Ensminger, Alexander W

    2016-12-16

    Pathogens deliver complex arsenals of translocated effector proteins to host cells during infection, but the extent to which these proteins are regulated once inside the eukaryotic cell remains poorly defined. Among all bacterial pathogens, Legionella pneumophila maintains the largest known set of translocated substrates, delivering over 300 proteins to the host cell via its Type IVB, Icm/Dot translocation system. Backed by a few notable examples of effector-effector regulation in L. pneumophila, we sought to define the extent of this phenomenon through a systematic analysis of effector-effector functional interaction. We used Saccharomyces cerevisiae, an established proxy for the eukaryotic host, to query > 108,000 pairwise genetic interactions between two compatible expression libraries of ~330 L. pneumophila-translocated substrates. While capturing all known examples of effector-effector suppression, we identify fourteen novel translocated substrates that suppress the activity of other bacterial effectors and one pair with synergistic activities. In at least nine instances, this regulation is direct-a hallmark of an emerging class of proteins called metaeffectors, or "effectors of effectors". Through detailed structural and functional analysis, we show that metaeffector activity derives from a diverse range of mechanisms, shapes evolution, and can be used to reveal important aspects of each cognate effector's function. Metaeffectors, along with other, indirect, forms of effector-effector modulation, may be a common feature of many intracellular pathogens-with unrealized potential to inform our understanding of how pathogens regulate their interactions with the host cell. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  10. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Science.gov (United States)

    Furuse, Yuki; Finethy, Ryan; Saka, Hector A; Xet-Mull, Ana M; Sisk, Dana M; Smith, Kristen L Jurcic; Lee, Sunhee; Coers, Jörn; Valdivia, Raphael H; Tobin, David M; Cullen, Bryan R

    2014-01-01

    MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.

  11. Search for microRNAs expressed by intracellular bacterial pathogens in infected mammalian cells.

    Directory of Open Access Journals (Sweden)

    Yuki Furuse

    Full Text Available MicroRNAs are expressed by all multicellular organisms and play a critical role as post-transcriptional regulators of gene expression. Moreover, different microRNA species are known to influence the progression of a range of different diseases, including cancer and microbial infections. A number of different human viruses also encode microRNAs that can attenuate cellular innate immune responses and promote viral replication, and a fungal pathogen that infects plants has recently been shown to express microRNAs in infected cells that repress host cell immune responses and promote fungal pathogenesis. Here, we have used deep sequencing of total expressed small RNAs, as well as small RNAs associated with the cellular RNA-induced silencing complex RISC, to search for microRNAs that are potentially expressed by intracellular bacterial pathogens and translocated into infected animal cells. In the case of Legionella and Chlamydia and the two mycobacterial species M. smegmatis and M. tuberculosis, we failed to detect any bacterial small RNAs that had the characteristics expected for authentic microRNAs, although large numbers of small RNAs of bacterial origin could be recovered. However, a third mycobacterial species, M. marinum, did express an ∼ 23-nt small RNA that was bound by RISC and derived from an RNA stem-loop with the characteristics expected for a pre-microRNA. While intracellular expression of this candidate bacterial microRNA was too low to effectively repress target mRNA species in infected cultured cells in vitro, artificial overexpression of this potential bacterial pre-microRNA did result in the efficient repression of a target mRNA. This bacterial small RNA therefore represents the first candidate microRNA of bacterial origin.

  12. Molecular evolutionary consequences of niche restriction in Francisella tularensis, a facultative intracellular pathogen.

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    Pär Larsson

    2009-06-01

    Full Text Available Francisella tularensis is a potent mammalian pathogen well adapted to intracellular habitats, whereas F. novicida and F. philomiragia are less virulent in mammals and appear to have less specialized lifecycles. We explored adaptations within the genus that may be linked to increased host association, as follows. First, we determined the genome sequence of F. tularensis subsp. mediasiatica, the only subspecies that had not been previously sequenced. This genome, and those of 12 other F. tularensis isolates, were then compared to the genomes of F. novicida (three isolates and F. philomiragia (one isolate. Signs of homologous recombination were found in approximately 19.2% of F. novicida and F. philomiragia genes, but none among F. tularensis genomes. In addition, random insertions of insertion sequence elements appear to have provided raw materials for secondary adaptive mutations in F. tularensis, e.g. for duplication of the Francisella Pathogenicity Island and multiplication of a putative glycosyl transferase gene. Further, the five major genetic branches of F. tularensis seem to have converged along independent routes towards a common gene set via independent losses of gene functions. Our observations suggest that despite an average nucleotide identity of >97%, F. tularensis and F. novicida have evolved as two distinct population lineages, the former characterized by clonal structure with weak purifying selection, the latter by more frequent recombination and strong purifying selection. F. tularensis and F. novicida could be considered the same bacterial species, given their high similarity, but based on the evolutionary analyses described in this work we propose retaining separate species names.

  13. Perforin-2 is essential for intracellular defense of parenchymal cells and phagocytes against pathogenic bacteria

    Science.gov (United States)

    McCormack, Ryan M; de Armas, Lesley R; Shiratsuchi, Motoaki; Fiorentino, Desiree G; Olsson, Melissa L; Lichtenheld, Mathias G; Morales, Alejo; Lyapichev, Kirill; Gonzalez, Louis E; Strbo, Natasa; Sukumar, Neelima; Stojadinovic, Olivera; Plano, Gregory V; Munson, George P; Tomic-Canic, Marjana; Kirsner, Robert S; Russell, David G; Podack, Eckhard R

    2015-01-01

    Perforin-2 (MPEG1) is a pore-forming, antibacterial protein with broad-spectrum activity. Perforin-2 is expressed constitutively in phagocytes and inducibly in parenchymal, tissue-forming cells. In vitro, Perforin-2 prevents the intracellular replication and proliferation of bacterial pathogens in these cells. Perforin-2 knockout mice are unable to control the systemic dissemination of methicillin-resistant Staphylococcus aureus (MRSA) or Salmonella typhimurium and perish shortly after epicutaneous or orogastric infection respectively. In contrast, Perforin-2-sufficient littermates clear the infection. Perforin-2 is a transmembrane protein of cytosolic vesicles -derived from multiple organelles- that translocate to and fuse with bacterium containing vesicles. Subsequently, Perforin-2 polymerizes and forms large clusters of 100 Å pores in the bacterial surface with Perforin-2 cleavage products present in bacteria. Perforin-2 is also required for the bactericidal activity of reactive oxygen and nitrogen species and hydrolytic enzymes. Perforin-2 constitutes a novel and apparently essential bactericidal effector molecule of the innate immune system. DOI: http://dx.doi.org/10.7554/eLife.06508.001 PMID:26402460

  14. Dual Targeting of Intracellular Pathogenic Bacteria with a Cleavable Conjugate of Kanamycin and an Antibacterial Cell-Penetrating Peptide.

    Science.gov (United States)

    Brezden, Anna; Mohamed, Mohamed F; Nepal, Manish; Harwood, John S; Kuriakose, Jerrin; Seleem, Mohamed N; Chmielewski, Jean

    2016-08-31

    Bacterial infection caused by intracellular pathogens, such as Mycobacterium, Salmonella, and Brucella, is a burgeoning global health epidemic that necessitates urgent action. However, the therapeutic value of a number of antibiotics, including aminoglycosides, against intracellular pathogenic bacteria is compromised due to their inability to traverse eukaryotic membranes. For this significant problem to be addressed, a cleavable conjugate of the antibiotic kanamycin and a nonmembrane lytic, broad-spectrum antimicrobial peptide with efficient mammalian cell penetration, P14LRR, was prepared. This approach allows kanamycin to enter mammalian cells as a conjugate linked via a tether that breaks down in the reducing environment within cells. Potent antimicrobial activity of the P14KanS conjugate was demonstrated in vitro, and this reducible conjugate effectively cleared intracellular pathogenic bacteria within macrophages more potently than that of a conjugate lacking the disulfide moiety. Notably, successful clearance of Mycobacterium tuberculosis within macrophages was observed with the dual antibiotic conjugate, and Salmonella levels were significantly reduced in an in vivo Caenorhabditis elegans model.

  15. Pursuing Intracellular Pathogens with Hyaluronan. From a 'Pro-Infection' Polymer to a Biomaterial for 'Trojan Horse' Systems.

    Science.gov (United States)

    Montanari, Elita; Di Meo, Chiara; Oates, Angela; Coviello, Tommasina; Matricardi, Pietro

    2018-04-18

    Hyaluronan (HA) is among the most important bioactive polymers in mammals, playing a key role in a number of biological functions. In the last decades, it has been increasingly studied as a biomaterial for drug delivery systems, thanks to its physico-chemical features and ability to target and enter certain cells. The most important receptor of HA is ‘Cluster of Differentiation 44’ (CD44), a cell surface glycoprotein over-expressed by a number of cancers and heavily involved in HA endocytosis. Moreover, CD44 is highly expressed by keratinocytes, activated macrophages and fibroblasts, all of which can act as ‘reservoirs’ for intracellular pathogens. Interestingly, both CD44 and HA appear to play a key role for the invasion and persistence of such microorganisms within the cells. As such, HA is increasingly recognised as a potential target for nano-carriers development, to pursuit and target intracellular pathogens, acting as a ‘Trojan Horse’. This review describes the biological relationship between HA, CD44 and the entry and survival of a number of pathogens within the cells and the subsequent development of HA-based nano-carriers for enhancing the intracellular activity of antimicrobials.

  16. Eosinophils subvert host resistance to an intracellular pathogen by instigating non-protective IL-4 in CCR2-/- mice.

    Science.gov (United States)

    Verma, A H; Bueter, C L; Rothenberg, M E; Deepe, G S

    2017-01-01

    Eosinophils contribute to type II immune responses in helminth infections and allergic diseases; however, their influence on intracellular pathogens is less clear. We previously reported that CCR2 -/- mice exposed to the intracellular fungal pathogen Histoplasma capsulatum exhibit dampened immunity caused by an early exaggerated interleukin (IL)-4 response. We sought to identify the cellular source promulgating IL-4 in infected mutant animals. Eosinophils were the principal instigators of non-protective IL-4 and depleting this granulocyte population improved fungal clearance in CCR2 -/- animals. The deleterious impact of eosinophilia on mycosis was also recapitulated in transgenic animals overexpressing eosinophils. Mechanistic examination of IL-4 induction revealed that phagocytosis of H. capsulatum via the pattern recognition receptor complement receptor (CR) 3 triggered the heightened IL-4 response in murine eosinophils. This phenomenon was conserved in human eosinophils; exposure of cells to the fungal pathogen elicited a robust IL-4 response. Thus, our findings elucidate a detrimental attribute of eosinophil biology in fungal infections that could potentially trigger a collapse in host defenses by instigating type II immunity.

  17. Hyperspectral Imaging Using Intracellular Spies: Quantitative Real-Time Measurement of Intracellular Parameters In Vivo during Interaction of the Pathogenic Fungus Aspergillus fumigatus with Human Monocytes.

    Directory of Open Access Journals (Sweden)

    Sara Mohebbi

    Full Text Available Hyperspectral imaging (HSI is a technique based on the combination of classical spectroscopy and conventional digital image processing. It is also well suited for the biological assays and quantitative real-time analysis since it provides spectral and spatial data of samples. The method grants detailed information about a sample by recording the entire spectrum in each pixel of the whole image. We applied HSI to quantify the constituent pH variation in a single infected apoptotic monocyte as a model system. Previously, we showed that the human-pathogenic fungus Aspergillus fumigatus conidia interfere with the acidification of phagolysosomes. Here, we extended this finding to monocytes and gained a more detailed analysis of this process. Our data indicate that melanised A. fumigatus conidia have the ability to interfere with apoptosis in human monocytes as they enable the apoptotic cell to recover from mitochondrial acidification and to continue with the cell cycle. We also showed that this ability of A. fumigatus is dependent on the presence of melanin, since a non-pigmented mutant did not stop the progression of apoptosis and consequently, the cell did not recover from the acidic pH. By conducting the current research based on the HSI, we could measure the intracellular pH in an apoptotic infected human monocyte and show the pattern of pH variation during 35 h of measurements. As a conclusion, we showed the importance of melanin for determining the fate of intracellular pH in a single apoptotic cell.

  18. Small non-coding RNAs: new insights in modulation of host immune response by intracellular bacterial pathogens

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    Waqas Ahmed

    2016-10-01

    Full Text Available Pathogenic bacteria possess intricate regulatory networks that temporally control the production of virulence factors, and enable the bacteria to survive and proliferate within host cell. Small non-coding RNAs (sRNAs have been identified as important regulators of gene expression in diverse biological contexts. Recent research has shown bacterial sRNAs involved in growth and development, cell proliferation, differentiation, metabolism, cell signaling and immune response through regulating protein–protein interactions or via their ability to base pair with RNA and DNA. In this review, we provide a brief overview of mechanism of action employed by immune-related sRNAs, their known functions in immunity, and how they can be integrated into regulatory circuits that govern virulence, which will facilitates to understand pathogenesis and the development of novel, more effective therapeutic approaches to treat infections caused by intracellular bacterial pathogens.

  19. Effects of ionizing radiation over the structure, metabolism and infectivity of a pathogenic protozoan, Toxoplasma gondii; Efeitos da radiacao ionizante sobre a estrutura, metabolismo e infectividade de um protozoario patogenico, Toxoplasma gondii (Nicole and Manceau, 1908)

    Energy Technology Data Exchange (ETDEWEB)

    Hiramoto, Roberto Mitsuyoshi

    1998-07-01

    The intracellular parasite Toxoplasma gondii (Apicomplexa), has as definitive host domestic and wild felines and as intermediate hosts most species of mammals and birds, Including man. The infection in man is usually asymptomatic, but can become a severe and lethal illness in some special groups like the fetus of primoinfected pregnant woman, or in AIDS and transplanted patients. The transmission is due to ingestion of food or water contaminated with oocysts from cat feces as well as raw or rare cooked cyst containing meet. There is no available vaccine against toxoplasmosis, with some reports of the use ionizing radiation in order to attenuate or suppress the parasite. These studies are promising, but more research is needed to optimize the radiation process and to clarify those alterations caused on T gondii.Using a increasing doses of {sup 60} Co irradiation on T.gondii tachyzoites, we studied many parameters such as morphology, both at optical and electron microscopy level, detection of DNA fragmentation, metabolism alterations (cellular oxidative burst, protein, nucleic acids and DNA synthesis), determination of the parasite survival both in in vivo and in vitro models, antigenicity and immunogenicity after the process, cellular invasion and irradiated tachyzoite induced protection. After definition of 200 Gy of {sup 60} Co irradiation as the lower radiation dose that suppress parasite growth in vitro and in vivo, we found no detectable changes in parasite viability, its cell invasion capacity or in its structural proteins. DNA fragmentation like apoptosis or alterations of the parasite metabolism were similarly not affected by radiation. Mice infection with irradiated parasites induce partial protection when these animals were re-inoculated with non irradiated virulent parasites, inducing greater specific IgG levels as well as a longer survival. Irradiated T.gondii maintains its the ability of invasion, even under radiation effects. Based on our results we

  20. Molecular mechanisms of cell-cell spread of intracellular bacterial pathogens.

    Science.gov (United States)

    Ireton, Keith

    2013-07-17

    Several bacterial pathogens, including Listeria monocytogenes, Shigella flexneri and Rickettsia spp., have evolved mechanisms to actively spread within human tissues. Spreading is initiated by the pathogen-induced recruitment of host filamentous (F)-actin. F-actin forms a tail behind the microbe, propelling it through the cytoplasm. The motile pathogen then encounters the host plasma membrane, forming a bacterium-containing protrusion that is engulfed by an adjacent cell. Over the past two decades, much progress has been made in elucidating mechanisms of F-actin tail formation. Listeria and Shigella produce tails of branched actin filaments by subverting the host Arp2/3 complex. By contrast, Rickettsia forms tails with linear actin filaments through a bacterial mimic of eukaryotic formins. Compared with F-actin tail formation, mechanisms controlling bacterial protrusions are less well understood. However, recent findings have highlighted the importance of pathogen manipulation of host cell-cell junctions in spread. Listeria produces a soluble protein that enhances bacterial protrusions by perturbing tight junctions. Shigella protrusions are engulfed through a clathrin-mediated pathway at 'tricellular junctions'--specialized membrane regions at the intersection of three epithelial cells. This review summarizes key past findings in pathogen spread, and focuses on recent developments in actin-based motility and the formation and internalization of bacterial protrusions.

  1. A new pathogen transmission mechanism in the ocean: the case of sea otter exposure to the land-parasite Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Fernanda F M Mazzillo

    Full Text Available Toxoplasma gondii is a land-derived parasite that infects humans and marine mammals. Infections are a significant cause of mortality for endangered southern sea otters (Enhydra lutris nereis, but the transmission mechanism is poorly understood. Otter exposure to T. gondii has been linked to the consumption of marine turban snails in kelp (Macrocystis pyrifera forests. It is unknown how turban snails acquire oocysts, as snails scrape food particles attached to surfaces, whereas T. gondii oocysts enter kelp beds as suspended particles via runoff. We hypothesized that waterborne T. gondii oocysts attach to kelp surfaces when encountering exopolymer substances (EPS forming the sticky matrix of biofilms on kelp, and thus become available to snails. Results of a dietary composition analysis of field-collected snails and of kelp biofilm indicate that snails graze the dense kelp-biofilm assemblage composed of pennate diatoms and bacteria inserted within the EPS gel-like matrix. To test whether oocysts attach to kelp blades via EPS, we designed a laboratory experiment simulating the kelp forest canopy in tanks spiked with T. gondii surrogate microspheres and controlled for EPS and transparent exopolymer particles (TEP - the particulate form of EPS. On average, 19% and 31% of surrogates were detected attached to kelp surfaces covered with EPS in unfiltered and filtered seawater treatments, respectively. The presence of TEP in the seawater did not increase surrogate attachment. These findings support a novel transport mechanism of T. gondii oocysts: as oocysts enter the kelp forest canopy, a portion adheres to the sticky kelp biofilms. Snails grazing this biofilm encounter oocysts as 'bycatch' and thereby deliver the parasite to sea otters that prey upon snails. This novel mechanism can have health implications beyond T. gondii and otters, as a similar route of pathogen transmission may be implicated with other waterborne pathogens to marine wildlife and

  2. Pathogenic adaptation of intracellular bacteria by rewiring a cis-regulatory input function.

    Science.gov (United States)

    Osborne, Suzanne E; Walthers, Don; Tomljenovic, Ana M; Mulder, David T; Silphaduang, Uma; Duong, Nancy; Lowden, Michael J; Wickham, Mark E; Waller, Ross F; Kenney, Linda J; Coombes, Brian K

    2009-03-10

    The acquisition of DNA by horizontal gene transfer enables bacteria to adapt to previously unexploited ecological niches. Although horizontal gene transfer and mutation of protein-coding sequences are well-recognized forms of pathogen evolution, the evolutionary significance of cis-regulatory mutations in creating phenotypic diversity through altered transcriptional outputs is not known. We show the significance of regulatory mutation for pathogen evolution by mapping and then rewiring a cis-regulatory module controlling a gene required for murine typhoid. Acquisition of a binding site for the Salmonella pathogenicity island-2 regulator, SsrB, enabled the srfN gene, ancestral to the Salmonella genus, to play a role in pathoadaptation of S. typhimurium to a host animal. We identified the evolved cis-regulatory module and quantified the fitness gain that this regulatory output accrues for the bacterium using competitive infections of host animals. Our findings highlight a mechanism of pathogen evolution involving regulatory mutation that is selected because of the fitness advantage the new regulatory output provides the incipient clones.

  3. An optimal method of iron starvation of the obligate intracellular pathogen, Chlamydia trachomatis

    Directory of Open Access Journals (Sweden)

    Christopher C. Thompson

    2011-02-01

    Full Text Available Iron is an essential cofactor in a number of critical biochemical reactions, and as such, its acquisition, storage, and metabolism is highly regulated in most organisms. The obligate intracellular bacterium, Chlamydia trachomatis experiences a developmental arrest when iron within the host is depleted. The nature of the iron starvation response in Chlamydia is relatively uncharacterized because of the likely inefficient method of iron depletion, which currently relies on the compound deferoxamine mesylate (DFO. Inefficient induction of the iron starvation response precludes the identification of iron-regulated genes. This report evaluated DFO with another iron chelator, 2,2’-bipyridyl (Bpdl and presented a systematic comparison of the two across a range of criteria in a single-treatment time-of-infection regimen. We demonstrate that the membrane permeable Bpdl was superior to DFO in the inhibition of chlamydia development, the induction of aberrant morphology, and the induction of an iron starvation transcriptional response in both host and bacteria. Furthermore, iron starvation using Bpdl identified the periplasmic iron binding protein-encoding ytgA gene as iron- responsive. Overall, the data present a compelling argument for the use of Bpdl, rather than DFO, in future iron starvation studies of chlamydia and other intracellular bacteria.

  4. Intracellular persisting Staphylococcus aureus is the major pathogen in recurrent tonsillitis.

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    Andreas E Zautner

    Full Text Available BACKGROUND: The two major indications for tonsillectomy are recurrent tonsillitis (RT and peritonsillar abscess (PTA. Unlike PTAs, which are primarily treated surgically, RT is often cured by tonsillectomy only after a series of failed drug therapy attempts. Although the bacteriological background of RT has been studied, the reason for the lack of success of conservative therapeutic approaches is not well understood. METHODS: In a prospective study, tonsil specimens from 130 RT patients and 124 PTA patients were examined for the presence of extra- and intracellular bacteria using antibiotic protection assays. Staphylococcus aureus isolates from RT patients were characterized by pulsed-field gel electrophoresis (PFGE, spa-typing and MSCRAMM-gene-PCR. Their ability for biofilm formation was tested and their cell invasiveness was confirmed by a flow cytometric invasion assay (FACS, fluorescent in situ hybridization (FISH and immunohistochemistry. FINDINGS: S. aureus was the predominant species (57.7% in RT patients, whereas Streptococcus pyogenes was most prevalent (20.2% in PTA patients. Three different assays (FACS, FISH, antibiotic protection assay showed that nearly all RT-associated S. aureus strains were located inside tonsillar cells. Correspondingly, the results of the MSCRAMM-gene-PCRs confirmed that 87% of these S. aureus isolates were invasive strains and not mere colonizers. Based upon PFGE analyses of genomic DNA and on spa-gene typing the vast majority of the S. aureus isolates belonged to different clonal lineages. CONCLUSIONS: Our results demonstrate that intracellular residing S. aureus is the most common cause of RT and indicate that S. aureus uses this location to survive the effects of antibiotics and the host immune response. A German translation of the Abstract is provided as supplementary material (Abstract S1.

  5. The Equine Antimicrobial Peptide eCATH1 Is Effective against the Facultative Intracellular Pathogen Rhodococcus equi in Mice

    Science.gov (United States)

    Schlusselhuber, Margot; Torelli, Riccardo; Martini, Cecilia; Leippe, Matthias; Cattoir, Vincent; Leclercq, Roland; Laugier, Claire; Grötzinger, Joachim; Sanguinetti, Maurizio

    2013-01-01

    Rhodococcus equi, the causal agent of rhodococcosis, is a major pathogen of foals and is also responsible for severe infections in immunocompromised humans. Of great concern, strains resistant to currently used antibiotics have emerged. As the number of drugs that are efficient in vivo is limited because of the intracellular localization of the bacterium inside macrophages, new active but cell-permeant drugs will be needed in the near future. In the present study, we evaluated, by in vitro and ex vivo experiments, the ability of the alpha-helical equine antimicrobial peptide eCATH1 to kill intracellular bacterial cells. Moreover, the therapeutic potential of the peptide was assessed in experimental rhodococcosis induced in mice, while the in vivo toxicity was evaluated by behavioral and histopathological analysis. The study revealed that eCATH1 significantly reduced the number of bacteria inside macrophages. Furthermore, the bactericidal potential of the peptide was maintained in vivo at doses that appeared to have no visible deleterious effects for the mice even after 7 days of treatment. Indeed, daily subcutaneous injections of 1 mg/kg body weight of eCATH1 led to a significant reduction of the bacterial load in organs comparable to that obtained after treatment with 10 mg/kg body weight of rifampin. Interestingly, the combination of the peptide with rifampin showed a synergistic interaction in both ex vivo and in vivo experiments. These results emphasize the therapeutic potential that eCATH1 represents in the treatment of rhodococcosis. PMID:23817377

  6. Intracellular Growth Is Dependent on Tyrosine Catabolism in the Dimorphic Fungal Pathogen Penicillium marneffei

    Science.gov (United States)

    Boyce, Kylie J.; McLauchlan, Alisha; Schreider, Lena; Andrianopoulos, Alex

    2015-01-01

    During infection, pathogens must utilise the available nutrient sources in order to grow while simultaneously evading or tolerating the host’s defence systems. Amino acids are an important nutritional source for pathogenic fungi and can be assimilated from host proteins to provide both carbon and nitrogen. The hpdA gene of the dimorphic fungus Penicillium marneffei, which encodes an enzyme which catalyses the second step of tyrosine catabolism, was identified as up-regulated in pathogenic yeast cells. As well as enabling the fungus to acquire carbon and nitrogen, tyrosine is also a precursor in the formation of two types of protective melanin; DOPA melanin and pyomelanin. Chemical inhibition of HpdA in P. marneffei inhibits ex vivo yeast cell production suggesting that tyrosine is a key nutrient source during infectious growth. The genes required for tyrosine catabolism, including hpdA, are located in a gene cluster and the expression of these genes is induced in the presence of tyrosine. A gene (hmgR) encoding a Zn(II)2-Cys6 binuclear cluster transcription factor is present within the cluster and is required for tyrosine induced expression and repression in the presence of a preferred nitrogen source. AreA, the GATA-type transcription factor which regulates the global response to limiting nitrogen conditions negatively regulates expression of cluster genes in the absence of tyrosine and is required for nitrogen metabolite repression. Deletion of the tyrosine catabolic genes in the cluster affects growth on tyrosine as either a nitrogen or carbon source and affects pyomelanin, but not DOPA melanin, production. In contrast to other genes of the tyrosine catabolic cluster, deletion of hpdA results in no growth within macrophages. This suggests that the ability to catabolise tyrosine is not required for macrophage infection and that HpdA has an additional novel role to that of tyrosine catabolism and pyomelanin production during growth in host cells. PMID:25812137

  7. Structure of the virulence-associated protein VapD from the intracellular pathogen Rhodococcus equi

    International Nuclear Information System (INIS)

    Whittingham, Jean L.; Blagova, Elena V.; Finn, Ciaran E.; Luo, Haixia; Miranda-CasoLuengo, Raúl; Turkenburg, Johan P.; Leech, Andrew P.; Walton, Paul H.; Murzin, Alexey G.; Meijer, Wim G.; Wilkinson, Anthony J.

    2014-01-01

    VapD is one of a set of highly homologous virulence-associated proteins from the multi-host pathogen Rhodococcus equi. The crystal structure reveals an eight-stranded β-barrel with a novel fold and a glycine rich ‘bald’ surface. Rhodococcus equi is a multi-host pathogen that infects a range of animals as well as immune-compromised humans. Equine and porcine isolates harbour a virulence plasmid encoding a homologous family of virulence-associated proteins associated with the capacity of R. equi to divert the normal processes of endosomal maturation, enabling bacterial survival and proliferation in alveolar macrophages. To provide a basis for probing the function of the Vap proteins in virulence, the crystal structure of VapD was determined. VapD is a monomer as determined by multi-angle laser light scattering. The structure reveals an elliptical, compact eight-stranded β-barrel with a novel strand topology and pseudo-twofold symmetry, suggesting evolution from an ancestral dimer. Surface-associated octyl-β-d-glucoside molecules may provide clues to function. Circular-dichroism spectroscopic analysis suggests that the β-barrel structure is preceded by a natively disordered region at the N-terminus. Sequence comparisons indicate that the core folds of the other plasmid-encoded virulence-associated proteins from R. equi strains are similar to that of VapD. It is further shown that sequences encoding putative R. equi Vap-like proteins occur in diverse bacterial species. Finally, the functional implications of the structure are discussed in the light of the unique structural features of VapD and its partial structural similarity to other β-barrel proteins

  8. Structure of the virulence-associated protein VapD from the intracellular pathogen Rhodococcus equi

    Energy Technology Data Exchange (ETDEWEB)

    Whittingham, Jean L.; Blagova, Elena V. [University of York, Heslington, York YO10 5DD (United Kingdom); Finn, Ciaran E.; Luo, Haixia; Miranda-CasoLuengo, Raúl [University College Dublin, Dublin (Ireland); Turkenburg, Johan P.; Leech, Andrew P.; Walton, Paul H. [University of York, Heslington, York YO10 5DD (United Kingdom); Murzin, Alexey G. [MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH (United Kingdom); Meijer, Wim G. [University College Dublin, Dublin (Ireland); Wilkinson, Anthony J., E-mail: tony.wilkinson@york.ac.uk [University of York, Heslington, York YO10 5DD (United Kingdom)

    2014-08-01

    VapD is one of a set of highly homologous virulence-associated proteins from the multi-host pathogen Rhodococcus equi. The crystal structure reveals an eight-stranded β-barrel with a novel fold and a glycine rich ‘bald’ surface. Rhodococcus equi is a multi-host pathogen that infects a range of animals as well as immune-compromised humans. Equine and porcine isolates harbour a virulence plasmid encoding a homologous family of virulence-associated proteins associated with the capacity of R. equi to divert the normal processes of endosomal maturation, enabling bacterial survival and proliferation in alveolar macrophages. To provide a basis for probing the function of the Vap proteins in virulence, the crystal structure of VapD was determined. VapD is a monomer as determined by multi-angle laser light scattering. The structure reveals an elliptical, compact eight-stranded β-barrel with a novel strand topology and pseudo-twofold symmetry, suggesting evolution from an ancestral dimer. Surface-associated octyl-β-d-glucoside molecules may provide clues to function. Circular-dichroism spectroscopic analysis suggests that the β-barrel structure is preceded by a natively disordered region at the N-terminus. Sequence comparisons indicate that the core folds of the other plasmid-encoded virulence-associated proteins from R. equi strains are similar to that of VapD. It is further shown that sequences encoding putative R. equi Vap-like proteins occur in diverse bacterial species. Finally, the functional implications of the structure are discussed in the light of the unique structural features of VapD and its partial structural similarity to other β-barrel proteins.

  9. Antibody-mediated immunity to the obligate intracellular bacterial pathogen Coxiella burnetii is Fc receptor- and complement-independent

    Directory of Open Access Journals (Sweden)

    Heinzen Robert A

    2009-05-01

    Full Text Available Abstract Background The obligate intracellular bacterial pathogen Coxiella burnetii causes the zoonosis Q fever. The intracellular niche of C. burnetii has led to the assumption that cell-mediated immunity is the most important immune component for protection against this pathogen. However, passive immunization with immune serum can protect naïve animals from challenge with virulent C. burnetii, indicating a role for antibody (Ab in protection. The mechanism of this Ab-mediated protection is unknown. Therefore, we conducted a study to determine whether Fc receptors (FcR or complement contribute to Ab-mediated immunity (AMI to C. burnetii. Results Virulent C. burnetii infects and replicates within human dendritic cells (DC without inducing their maturation or activation. We investigated the effects of Ab opsonized C. burnetii on human monocyte-derived and murine bone marrow-derived DC. Infection of DC with Ab-opsonized C. burnetii resulted in increased expression of maturation markers and inflammatory cytokine production. Bacteria that had been incubated with naïve serum had minimal effect on DC, similar to virulent C. burnetii alone. The effect of Ab opsonized C. burnetii on DC was FcR dependent as evidenced by a reduced response of DC from FcR knockout (FcR k/o compared to C57Bl/6 (B6 mice. To address the potential role of FcR in Ab-mediated protection in vivo, we compared the response of passively immunized FcR k/o mice to the B6 controls. Interestingly, we found that FcR are not essential for AMI to C. burnetii in vivo. We subsequently examined the role of complement in AMI by passively immunizing and challenging several different strains of complement-deficient mice and found that AMI to C. burnetii is also complement-independent. Conclusion Despite our data showing FcR-dependent stimulation of DC in vitro, Ab-mediated immunity to C. burnetii in vivo is FcR-independent. We also found that passive immunity to this pathogen is independent of

  10. NK Cell-Mediated Regulation of Protective Memory Responses against Intracellular Ehrlichial Pathogens.

    Directory of Open Access Journals (Sweden)

    Samar Habib

    Full Text Available Ehrlichiae are gram-negative obligate intracellular bacteria that cause potentially fatal human monocytic ehrlichiosis. We previously showed that natural killer (NK cells play a critical role in host defense against Ehrlichia during primary infection. However, the contribution of NK cells to the memory response against Ehrlichia remains elusive. Primary infection of C57BL/6 mice with Ehrlichia muris provides long-term protection against a second challenge with the highly virulent Ixodes ovatus Ehrlichia (IOE, which ordinarily causes fatal disease in naïve mice. Here, we show that the depletion of NK cells in E. muris-primed mice abrogates the protective memory response against IOE. Approximately, 80% of NK cell-depleted E. muris-primed mice succumbed to lethal IOE infection on days 8-10 after IOE infection, similar to naïve mice infected with the same dose of IOE. The lack of a recall response in NK cell-depleted mice correlated with an increased bacterial burden, extensive liver injury, decreased frequency of Ehrlichia-specific IFN-γ-producing memory CD4+ and CD8+ T-cells, and a low titer of Ehrlichia-specific antibodies. Intraperitoneal infection of mice with E. muris resulted in the production of IL-15, IL-12, and IFN-γ as well as an expansion of activated NKG2D+ NK cells. The adoptive transfer of purified E. muris-primed hepatic and splenic NK cells into Rag2-/-Il2rg-/- recipient mice provided protective immunity against challenge with E. muris. Together, these data suggest that E. muris-induced memory-like NK cells, which contribute to the protective, recall response against Ehrlichia.

  11. Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major.

    Science.gov (United States)

    Ricci-Azevedo, Rafael; Oliveira, Aline Ferreira; Conrado, Marina C A V; Carvalho, Fernanda Caroline; Roque-Barreira, Maria Cristina

    2016-04-01

    ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1) immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS), form neutrophil extracellular traps (NETs) and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF) and interleukin-1beta (IL-1β) release; otherwise, transforming growth factor-beta (TGF-β) production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be considered an

  12. Neutrophils Contribute to the Protection Conferred by ArtinM against Intracellular Pathogens: A Study on Leishmania major.

    Directory of Open Access Journals (Sweden)

    Rafael Ricci-Azevedo

    2016-04-01

    Full Text Available ArtinM, a D-mannose binding lectin from Artocarpus heterophyllus, has immunomodulatory activities through its interaction with N-glycans of immune cells, culminating with the establishment of T helper type 1 (Th1 immunity. This interaction protects mice against intracellular pathogens, including Leishmania major and Leishmania amazonensis. ArtinM induces neutrophils activation, which is known to account for both resistance to pathogens and host tissue injury. Although exacerbated inflammation was not observed in ArtinM-treated animals, assessment of neutrophil responses to ArtinM is required to envisage its possible application to design a novel immunomodulatory agent based on carbohydrate recognition. Herein, we focus on the mechanisms through which neutrophils contribute to ArtinM-induced protection against Leishmania, without exacerbating inflammation. For this purpose, human neutrophils treated with ArtinM and infected with Leishmania major were analyzed together with untreated and uninfected controls, based on their ability to eliminate the parasite, release cytokines, degranulate, produce reactive oxygen species (ROS, form neutrophil extracellular traps (NETs and change life span. We demonstrate that ArtinM-stimulated neutrophils enhanced L. major clearance and at least duplicated tumor necrosis factor (TNF and interleukin-1beta (IL-1β release; otherwise, transforming growth factor-beta (TGF-β production was reduced by half. Furthermore, ROS production and cell degranulation were augmented. The life span of ArtinM-stimulated neutrophils decreased and they did not form NETs when infected with L. major. We postulate that the enhanced leishmanicidal ability of ArtinM-stimulated neutrophils is due to augmented release of inflammatory cytokines, ROS production, and cell degranulation, whereas host tissue integrity is favored by their shortened life span and the absence of NET formation. Our results reinforce the idea that ArtinM may be

  13. Vacuolar zinc transporter Zrc1 is required for detoxification of excess intracellular zinc in the human fungal pathogen Cryptococcus neoformans.

    Science.gov (United States)

    Cho, Minsu; Hu, Guanggan; Caza, Mélissa; Horianopoulos, Linda C; Kronstad, James W; Jung, Won Hee

    2018-01-01

    Zinc is an important transition metal in all living organisms and is required for numerous biological processes. However, excess zinc can also be toxic to cells and cause cellular stress. In the model fungus Saccharomyces cerevisiae, a vacuolar zinc transporter, Zrc1, plays important roles in the storage and detoxification of excess intracellular zinc to protect the cell. In this study, we identified an ortholog of the S. cerevisiae ZRC1 gene in the human fungal pathogen Cryptococcus neoformans. Zrc1 was localized in the vacuolar membrane in C. neoformans, and a mutant lacking ZRC1 showed significant growth defects under high-zinc conditions. These results suggested a role for Zrc1 in zinc detoxification. However, contrary to our expectation, the expression of Zrc1 was induced in cells grown in zinc-limited conditions and decreased upon the addition of zinc. These expression patterns were similar to those of Zip1, the high-affinity zinc transporter in the plasma membrane of C. neoformans. Furthermore, we used the zrc1 mutant in a murine model of cryptococcosis to examine whether a mammalian host could inhibit the survival of C. neoformans using zinc toxicity. We found that the mutant showed no difference in virulence compared with the wildtype strain. This result suggests that Zrc1-mediated zinc detoxification is not required for the virulence of C. neoformans, and imply that zinc toxicity may not be an important aspect of the host immune response to the fungus.

  14. Neutrophils, dendritic cells and Toxoplasma.

    Science.gov (United States)

    Denkers, Eric Y; Butcher, Barbara A; Del Rio, Laura; Bennouna, Soumaya

    2004-03-09

    Toxoplasma gondii rapidly elicits strong Type 1 cytokine-based immunity. The necessity for this response is well illustrated by the example of IFN-gamma and IL-12 gene knockout mice that rapidly succumb to the effects of acute infection. The parasite itself is skilled at sparking complex interactions in the innate immune system that lead to protective immunity. Neutrophils are one of the first cell types to arrive at the site of infection, and the cells release several proinflammatory cytokines and chemokines in response to Toxoplasma. Dendritic cells are an important source of IL-12 during infection with T. gondii and other microbial pathogens, and they are also specialized for high-level antigen presentation to T lymphocytes. Tachyzoites express at least two types of molecules that trigger innate immune cell cytokine production. One of these involves Toll-like receptor/MyD88 pathways common to many microbial pathogens. The second pathway is less conventional and involves molecular mimicry between a parasite cyclophilin and host CC chemokine receptor 5-binding ligands. Neutrophils, dendritic cells and Toxoplasma work together to elicit the immune response required for host survival. Cytokine and chemokine cross-talk between parasite-triggered neutrophils and dendritic cells results in recruitment, maturation and activation of the latter. Neutrophil-empowered dendritic cells possess properties expected of highly potent antigen presenting cells that drive T helper 1 generation.

  15. Eosinophils Subvert Host Resistance to an Intracellular Pathogen by Instigating Non-Protective IL-4 in CCR2−/− Mice

    Science.gov (United States)

    Verma, Akash H.; Bueter, Chelsea L.; Rothenberg, Marc E.; Deepe, George S.

    2016-01-01

    Eosinophils contribute to type II immune responses in helminth infections and allergic diseases, however, their influence on intracellular pathogens is less clear. We previously reported that CCR2−/− mice exposed to the intracellular fungal pathogen Histoplasma capsulatum exhibit dampened immunity caused by an early exaggerated IL-4 response. We sought to identify the cellular source promulgating interleukin (IL)-4 in infected mutant animals. Eosinophils were the principal instigators of non-protective IL-4 and depleting this granulocyte population improved fungal clearance in CCR2−/− animals. The deleterious impact of eosinophilia on mycosis was also recapitulated in transgenic animals overexpressing eosinophils. Mechanistic examination of IL-4 induction revealed that phagocytosis of H. capsulatum via the pattern recognition receptor complement receptor (CR) 3 triggered the heightened IL-4 response in murine eosinophils. This phenomenon was conserved in human eosinophils; exposure of cells to the fungal pathogen elicited a robust IL-4 response. Thus, our findings elucidate a detrimental attribute of eosinophil biology in fungal infections that could potentially trigger a collapse in host defenses by instigating type II immunity. PMID:27049063

  16. Possible role of Toxoplasma gondii in brain cancer through modulation of host microRNAs

    Directory of Open Access Journals (Sweden)

    Thirugnanam Sivasakthivel

    2013-02-01

    Full Text Available Abstract Background 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-Toxoplasma antibodies and incidences of brain cancer have led to the notion that Toxoplasma infections increase the risk of brain cancer. However, molecular events involved in Toxoplasma induced brain cancers are not well understood. Presentation of the hypothesis Toxoplasma gains control of host cell functions including proliferation and apoptosis by channelizing parasite proteins into the cell cytoplasm and some of the proteins are targeted to the host nucleus. Recent studies have shown that Toxoplasma is capable of manipulating host micro RNAs (miRNAs, which play a central role in post-transcriptional regulation of gene expression. Therefore, we hypothesize that Toxoplasma promotes brain carcinogenesis by altering the host miRNAome using parasitic proteins and/or miRNAs. Testing the hypothesis The miRNA expression profiles of brain cancer specimens obtained from patients infected with Toxoplasma could be analyzed and compared with that of normal tissues as well as brain cancer tissues from Toxoplasma uninfected individuals to identify dysregulated miRNAs in Toxoplasma-driven brain cancer cells. Identified miRNAs will be further confirmed by studying cancer related miRNA profiles of the different types of brain cells before and after Toxoplasma infection using cell lines and experimental animals. Expected outcome The miRNAs specifically associated with brain cancers that are caused by Toxoplasma infection will be identified. Implications of the hypothesis Toxoplasma infection may promote initiation and progression of cancer by modifying the miRNAome in brain cells. If this hypothesis is true, the outcome of this research would lead to the development of novel biomarkers and

  17. The Orphan Nuclear Receptor TLX Is an Enhancer of STAT1-Mediated Transcription and Immunity to Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Daniel P Beiting

    2015-07-01

    Full Text Available The protozoan parasite, Toxoplasma, like many intracellular pathogens, suppresses interferon gamma (IFN-γ-induced signal transducer and activator of transcription 1 (STAT1 activity. We exploited this well-defined host-pathogen interaction as the basis for a high-throughput screen, identifying nine transcription factors that enhance STAT1 function in the nucleus, including the orphan nuclear hormone receptor TLX. Expression profiling revealed that upon IFN-γ treatment TLX enhances the output of a subset of IFN-γ target genes, which we found is dependent on TLX binding at those loci. Moreover, infection of TLX deficient mice with the intracellular parasite Toxoplasma results in impaired production of the STAT1-dependent cytokine interleukin-12 by dendritic cells and increased parasite burden in the brain during chronic infection. These results demonstrate a previously unrecognized role for this orphan nuclear hormone receptor in regulating STAT1 signaling and host defense and reveal that STAT1 activity can be modulated in a context-specific manner by such "modifiers."

  18. The Orphan Nuclear Receptor TLX Is an Enhancer of STAT1-Mediated Transcription and Immunity to Toxoplasma gondii.

    Science.gov (United States)

    Beiting, Daniel P; Hidano, Shinya; Baggs, Julie E; Geskes, Jeanne M; Fang, Qun; Wherry, E John; Hunter, Christopher A; Roos, David S; Cherry, Sara

    2015-07-01

    The protozoan parasite, Toxoplasma, like many intracellular pathogens, suppresses interferon gamma (IFN-γ)-induced signal transducer and activator of transcription 1 (STAT1) activity. We exploited this well-defined host-pathogen interaction as the basis for a high-throughput screen, identifying nine transcription factors that enhance STAT1 function in the nucleus, including the orphan nuclear hormone receptor TLX. Expression profiling revealed that upon IFN-γ treatment TLX enhances the output of a subset of IFN-γ target genes, which we found is dependent on TLX binding at those loci. Moreover, infection of TLX deficient mice with the intracellular parasite Toxoplasma results in impaired production of the STAT1-dependent cytokine interleukin-12 by dendritic cells and increased parasite burden in the brain during chronic infection. These results demonstrate a previously unrecognized role for this orphan nuclear hormone receptor in regulating STAT1 signaling and host defense and reveal that STAT1 activity can be modulated in a context-specific manner by such "modifiers."

  19. Genome sequencing of the lizard parasite Leishmania tarentolae reveals loss of genes associated to the intracellular stage of human pathogenic species

    Science.gov (United States)

    Raymond, Frédéric; Boisvert, Sébastien; Roy, Gaétan; Ritt, Jean-François; Légaré, Danielle; Isnard, Amandine; Stanke, Mario; Olivier, Martin; Tremblay, Michel J.; Papadopoulou, Barbara; Ouellette, Marc; Corbeil, Jacques

    2012-01-01

    The Leishmania tarentolae Parrot-TarII strain genome sequence was resolved to an average 16-fold mean coverage by next-generation DNA sequencing technologies. This is the first non-pathogenic to humans kinetoplastid protozoan genome to be described thus providing an opportunity for comparison with the completed genomes of pathogenic Leishmania species. A high synteny was observed between all sequenced Leishmania species. A limited number of chromosomal regions diverged between L. tarentolae and L. infantum, while remaining syntenic to L. major. Globally, >90% of the L. tarentolae gene content was shared with the other Leishmania species. We identified 95 predicted coding sequences unique to L. tarentolae and 250 genes that were absent from L. tarentolae. Interestingly, many of the latter genes were expressed in the intracellular amastigote stage of pathogenic species. In addition, genes coding for products involved in antioxidant defence or participating in vesicular-mediated protein transport were underrepresented in L. tarentolae. In contrast to other Leishmania genomes, two gene families were expanded in L. tarentolae, namely the zinc metallo-peptidase surface glycoprotein GP63 and the promastigote surface antigen PSA31C. Overall, L. tarentolae's gene content appears better adapted to the promastigote insect stage rather than the amastigote mammalian stage. PMID:21998295

  20. Mechanisms of cellular invasion by intracellular parasites.

    Science.gov (United States)

    Walker, Dawn M; Oghumu, Steve; Gupta, Gaurav; McGwire, Bradford S; Drew, Mark E; Satoskar, Abhay R

    2014-04-01

    Numerous disease-causing parasites must invade host cells in order to prosper. Collectively, such pathogens are responsible for a staggering amount of human sickness and death throughout the world. Leishmaniasis, Chagas disease, toxoplasmosis, and malaria are neglected diseases and therefore are linked to socio-economical and geographical factors, affecting well-over half the world's population. Such obligate intracellular parasites have co-evolved with humans to establish a complexity of specific molecular parasite-host cell interactions, forming the basis of the parasite's cellular tropism. They make use of such interactions to invade host cells as a means to migrate through various tissues, to evade the host immune system, and to undergo intracellular replication. These cellular migration and invasion events are absolutely essential for the completion of the lifecycles of these parasites and lead to their for disease pathogenesis. This review is an overview of the molecular mechanisms of protozoan parasite invasion of host cells and discussion of therapeutic strategies, which could be developed by targeting these invasion pathways. Specifically, we focus on four species of protozoan parasites Leishmania, Trypanosoma cruzi, Plasmodium, and Toxoplasma, which are responsible for significant morbidity and mortality.

  1. The compact genome of the plant pathogen Plasmodiophora brassicae is adapted to intracellular interactions with host Brassica spp.

    Science.gov (United States)

    Rolfe, Stephen A; Strelkov, Stephen E; Links, Matthew G; Clarke, Wayne E; Robinson, Stephen J; Djavaheri, Mohammad; Malinowski, Robert; Haddadi, Parham; Kagale, Sateesh; Parkin, Isobel A P; Taheri, Ali; Borhan, M Hossein

    2016-03-31

    The protist Plasmodiophora brassicae is a soil-borne pathogen of cruciferous species and the causal agent of clubroot disease of Brassicas including agriculturally important crops such as canola/rapeseed (Brassica napus). P. brassicae has remained an enigmatic plant pathogen and is a rare example of an obligate biotroph that resides entirely inside the host plant cell. The pathogen is the cause of severe yield losses and can render infested fields unsuitable for Brassica crop growth due to the persistence of resting spores in the soil for up to 20 years. To provide insight into the biology of the pathogen and its interaction with its primary host B. napus, we produced a draft genome of P. brassicae pathotypes 3 and 6 (Pb3 and Pb6) that differ in their host range. Pb3 is highly virulent on B. napus (but also infects other Brassica species) while Pb6 infects only vegetable Brassica crops. Both the Pb3 and Pb6 genomes are highly compact, each with a total size of 24.2 Mb, and contain less than 2 % repetitive DNA. Clustering of genome-wide single nucleotide polymorphisms (SNP) of Pb3, Pb6 and three additional re-sequenced pathotypes (Pb2, Pb5 and Pb8) shows a high degree of correlation of cluster grouping with host range. The Pb3 genome features significant reduction of intergenic space with multiple examples of overlapping untranslated regions (UTRs). Dependency on the host for essential nutrients is evident from the loss of genes for the biosynthesis of thiamine and some amino acids and the presence of a wide range of transport proteins, including some unique to P. brassicae. The annotated genes of Pb3 include those with a potential role in the regulation of the plant growth hormones cytokinin and auxin. The expression profile of Pb3 genes, including putative effectors, during infection and their potential role in manipulation of host defence is discussed. The P. brassicae genome sequence reveals a compact genome, a dependency of the pathogen on its host for some

  2. Increased apoptosis skull of pups born to Toxoplasma gondii ...

    African Journals Online (AJOL)

    Background: Toxoplasma gondii is an intracellular obligate protozoan parasite that infects most warm-blooded animals including humans. It can cause congenital infection with clinical symptoms ranging from mild to severe including microcephaly. At the cellular level, infection T. gondii causes apoptosis in some tissues and ...

  3. Proteome profiling and functional classification of intracellular proteins from conidia of the human-pathogenic mold Aspergillus fumigatus.

    Science.gov (United States)

    Teutschbein, Janka; Albrecht, Daniela; Pötsch, Maria; Guthke, Reinhard; Aimanianda, Vishukumar; Clavaud, Cécile; Latgé, Jean-Paul; Brakhage, Axel A; Kniemeyer, Olaf

    2010-07-02

    Aspergillus fumigatus is a ubiquitously distributed filamentous fungus that has emerged as one of the most serious life-threatening pathogens in immunocompromised patients. The mechanisms for its pathogenicity are poorly understood. Here, we analyzed the proteome of dormant A. fumigatus conidia as the fungal entity having the initial contact with the host. Applying two-dimensional polyacrylamide gel electrophoresis (2-D PAGE), we established a 2-D reference map of conidial proteins. By MALDI-TOF mass spectrometry, we identified a total number of 449 different proteins. We show that 57 proteins of our map are over-represented in resting conidia compared to mycelium. Enzymes involved in reactive oxygen intermediates (ROI) detoxification, pigment biosynthesis, and conidial rodlet layer formation were highly abundant in A. fumigatus spores and most probably account for their enormous stress resistance. Interestingly, pyruvate decarboxylase and alcohol dehydrogenase were detectable in dormant conidia, suggesting that alcoholic fermentation plays a role during dormancy or early germination. Moreover, we show that enzymes for rapid reactivation of protein biosynthesis and metabolic processes are preserved in resting conidia, which therefore feature the potential to immediately respond to an environmental stimulus by germination. The generated data lay the foundations for further proteomic analyses and a better understanding of fungal pathogenesis.

  4. Understanding mechanisms and the role of differentiation in pathogenesis of Toxoplasma gondii: a review

    Directory of Open Access Journals (Sweden)

    William J Sullivan Jr

    2009-03-01

    Full Text Available Parasite differentiation from proliferating tachyzoites into latent bradyzoites is central to pathogenesis and transmission of the intracellular protozoan pathogen Toxoplasma gondii. The presence of bradyzoite-containing cysts in human hosts and their subsequent rupture can cause life-threatening recrudescence of acute infection in the immunocompromised and cyst formation in other animals contributes to zoonotic transmission and widespread dissemination of the parasite. In this review, we discuss the evidence showing how the clinically relevant process of bradyzoite differentiation is regulated at both transcriptional and post-transcriptional levels. Specific regulatory factors implicated in modulating bradyzoite differentiation include promoter-based cis-elements, epigenetic modifications and protein translation control through eukaryotic initiation factor -2 (eIF2. In addition to a summary of the current state of knowledge in these areas we discuss the pharmacological ramifications and pose some questions for future research.

  5. Toxoplasmosis (Toxoplasma infection) Treatment

    Science.gov (United States)

    ... Form Controls Cancel Submit Search the CDC Parasites - Toxoplasmosis (Toxoplasma infection) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Toxoplasmosis General Information Toxoplasmosis FAQs Toxoplasmosis & Pregnancy FAQs Epidemiology & ...

  6. The steroid catabolic pathway of the intracellular pathogen Rhodococcus equi is important for pathogenesis and a target for vaccine development.

    Directory of Open Access Journals (Sweden)

    R van der Geize

    2011-08-01

    Full Text Available Rhodococcus equi causes fatal pyogranulomatous pneumonia in foals and immunocompromised animals and humans. Despite its importance, there is currently no effective vaccine against the disease. The actinobacteria R. equi and the human pathogen Mycobacterium tuberculosis are related, and both cause pulmonary diseases. Recently, we have shown that essential steps in the cholesterol catabolic pathway are involved in the pathogenicity of M. tuberculosis. Bioinformatic analysis revealed the presence of a similar cholesterol catabolic gene cluster in R. equi. Orthologs of predicted M. tuberculosis virulence genes located within this cluster, i.e. ipdA (rv3551, ipdB (rv3552, fadA6 and fadE30, were identified in R. equi RE1 and inactivated. The ipdA and ipdB genes of R. equi RE1 appear to constitute the α-subunit and β-subunit, respectively, of a heterodimeric coenzyme A transferase. Mutant strains RE1ΔipdAB and RE1ΔfadE30, but not RE1ΔfadA6, were impaired in growth on the steroid catabolic pathway intermediates 4-androstene-3,17-dione (AD and 3aα-H-4α(3'-propionic acid-5α-hydroxy-7aβ-methylhexahydro-1-indanone (5α-hydroxy-methylhexahydro-1-indanone propionate; 5OH-HIP. Interestingly, RE1ΔipdAB and RE1ΔfadE30, but not RE1ΔfadA6, also displayed an attenuated phenotype in a macrophage infection assay. Gene products important for growth on 5OH-HIP, as part of the steroid catabolic pathway, thus appear to act as factors involved in the pathogenicity of R. equi. Challenge experiments showed that RE1ΔipdAB could be safely administered intratracheally to 2 to 5 week-old foals and oral immunization of foals even elicited a substantial protective immunity against a virulent R. equi strain. Our data show that genes involved in steroid catabolism are promising targets for the development of a live-attenuated vaccine against R. equi infections.

  7. TmpL, a transmembrane protein required for intracellular redox homeostasis and virulence in a plant and an animal fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Kwang-Hyung Kim

    2009-11-01

    Full Text Available The regulation of intracellular levels of reactive oxygen species (ROS is critical for developmental differentiation and virulence of many pathogenic fungi. In this report we demonstrate that a novel transmembrane protein, TmpL, is necessary for regulation of intracellular ROS levels and tolerance to external ROS, and is required for infection of plants by the necrotroph Alternaria brassicicola and for infection of mammals by the human pathogen Aspergillus fumigatus. In both fungi, tmpL encodes a predicted hybrid membrane protein containing an AMP-binding domain, six putative transmembrane domains, and an experimentally-validated FAD/NAD(P-binding domain. Localization and gene expression analyses in A. brassicicola indicated that TmpL is associated with the Woronin body, a specialized peroxisome, and strongly expressed during conidiation and initial invasive growth in planta. A. brassicicola and A. fumigatus DeltatmpL strains exhibited abnormal conidiogenesis, accelerated aging, enhanced oxidative burst during conidiation, and hypersensitivity to oxidative stress when compared to wild-type or reconstituted strains. Moreover, A. brassicicola DeltatmpL strains, although capable of initial penetration, exhibited dramatically reduced invasive growth on Brassicas and Arabidopsis. Similarly, an A. fumigatus DeltatmpL mutant was dramatically less virulent than the wild-type and reconstituted strains in a murine model of invasive aspergillosis. Constitutive expression of the A. brassicicola yap1 ortholog in an A. brassicicola DeltatmpL strain resulted in high expression levels of genes associated with oxidative stress tolerance. Overexpression of yap1 in the DeltatmpL background complemented the majority of observed developmental phenotypic changes and partially restored virulence on plants. Yap1-GFP fusion strains utilizing the native yap1 promoter exhibited constitutive nuclear localization in the A. brassicicola DeltatmpL background. Collectively, we

  8. Mannose-binding lectin and l-ficolin polymorphisms in patients with community-acquired pneumonia caused by intracellular pathogens.

    Science.gov (United States)

    van Kempen, Gijs; Meijvis, Sabine; Endeman, Henrik; Vlaminckx, Bart; Meek, Bob; de Jong, Ben; Rijkers, Ger; Bos, Willem Jan

    2017-05-01

    Community-acquired pneumonia (CAP) is the leading infectious disease requiring hospitalization in the western world. Genetic variability affecting the host response to infection may play a role in susceptibility and outcome in patients with CAP. Mannose-binding lectin (MBL) and l-ficolin (l-FCN) are two important activators of the complement system and they can enhance phagocytosis by opsonization. In a prospective cohort of 505 Dutch patients with CAP and 227 control participants we studied whether polymorphisms in the MBL (MBL2) and FCN (FCN2) genes influenced susceptibility and outcome. No difference in frequency of these genotypes was found between patients with CAP in general and controls. However, the +6424G>T single nucleotide polymorphism (SNP) in FCN2 was more common in patients with a Coxiella burnetii pneumonia (P = 0·014). Moreover, the haplotypes coding for the highest MBL serum levels (YA/YA and YA/XA) predisposed to atypical pneumonia (C. burnetii, Legionella or Chlamydia species or Mycoplasma pneumoniae) compared with controls (P = 0·016). Furthermore, patients with these haplotypes were more often bacteraemic (P = 0·019). It can therefore be concluded that MBL2 and FCN2 polymorphisms are not major risk factors for CAP in general, but that the +6424G>T SNP in the FCN2 gene predisposes to C. burnetii pneumonia. In addition, patients with genotypes corresponding with high serum MBL levels are at risk for atypical pneumonia, possibly caused by enhanced phagocytosis, thereby promoting cell entry of these intracellular bacteria. © 2016 The Authors. Immunology Published by John Wiley & Sons Ltd.

  9. Taxonomy Icon Data: Toxoplasma gondii [Taxonomy Icon

    Lifescience Database Archive (English)

    Full Text Available Toxoplasma gondii Toxoplasma gondii Toxoplasma_gondii_L.png Toxoplasma_gondii_NL.png Toxoplasma..._gondii_S.png Toxoplasma_gondii_NS.png http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Toxoplasma...+gondii&t=L http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Toxoplasma+gondii&t=NL http://biosciencedbc.j...p/taxonomy_icon/icon.cgi?i=Toxoplasma+gondii&t=S http://biosciencedbc.jp/taxonomy_icon/icon.cgi?i=Toxoplas...ma+gondii&t=NS http://togodb.biosciencedbc.jp/togodb/view/taxonomy_icon_comment_en?species_id=113 ...

  10. Seroprevalence of Toxoplasma gondii in Western Romania.

    Science.gov (United States)

    Olariu, Tudor Rares; Petrescu, Cristina; Darabus, Gheorghe; Lighezan, Rodica; Mazilu, Octavian

    2015-08-01

    Toxoplasma gondii is an obligate intracellular parasite that most commonly causes asymptomatic infection in immunocompetent hosts, but can have devastating consequences in congenitally infected infants and immunocompromised patients. We evaluated the seroprevalence of T. gondii in the general population in Western Romania. Sera from 304 individuals were analysed with the Pastorex Toxo test, which allows the simultaneous detection of T. gondii IgG and/or IgM antibodies. T. gondii antibodies were demonstrated in 197 individuals (64.8%) and the prevalence increased with age: 35.0% in those Romania.

  11. Cancer in the parasitic protozoans Trypanosoma brucei and Toxoplasma gondii.

    Science.gov (United States)

    Lun, Zhao-Rong; Lai, De-Hua; Wen, Yan-Zi; Zheng, Ling-Ling; Shen, Ji-Long; Yang, Ting-Bo; Zhou, Wen-Liang; Qu, Liang-Hu; Hide, Geoff; Ayala, Francisco J

    2015-07-21

    Cancer is a general name for more than 100 malignant diseases. It is postulated that all cancers start from a single abnormal cell that grows out of control. Untreated cancers can cause serious consequences and deaths. Great progress has been made in cancer research that has significantly improved our knowledge and understanding of the nature and mechanisms of the disease, but the origins of cancer are far from being well understood due to the limitations of suitable model systems and to the complexities of the disease. In view of the fact that cancers are found in various species of vertebrates and other metazoa, here, we suggest that cancer also occurs in parasitic protozoans such as Trypanosoma brucei, a blood parasite, and Toxoplasma gondii, an obligate intracellular pathogen. Without treatment, these protozoan cancers may cause severe disease and death in mammals, including humans. The simpler genomes of these single-cell organisms, in combination with their complex life cycles and fascinating life cycle differentiation processes, may help us to better understand the origins of cancers and, in particular, leukemias.

  12. On the determination of Toxoplasma gondii virulence in mice

    Science.gov (United States)

    Toxoplasma gondii is one of the most successful pathogens on earth, capable of infecting mammals and birds. Numerous papers and reports are published on isolation of T .gondii from various natural sources worldwide. The house mouse (Mus musculus) has been used as the laboratory animal model to deter...

  13. Pregnancy and Toxoplasma Infection

    Directory of Open Access Journals (Sweden)

    Cihan Cetin

    2016-12-01

    Full Text Available Toxoplasmosis is an infectious disease caused by a protozoa named Toxoplasma gondii. It is a very important disease because it is related to fetal anomalies and poor perinatal outcomes like abortus and stillbirth. It spreads via uncooked meat and contaminated food. Timely and appropriate treatment and management of this infection prenatally reduces the risk of serious neurological sequelae. Therefore it is crucial that clinician who takes care of pregnant women know this infection deeply. In this review we aimed to summarize the prenatal diagnosis, complications and treatment of toxoplasma infection. [Archives Medical Review Journal 2016; 25(4.000: 457-466

  14. Cell Death of Gamma Interferon-Stimulated Human Fibroblasts upon Toxoplasma gondii Infection Induces Early Parasite Egress and Limits Parasite Replication

    NARCIS (Netherlands)

    Niedelman, Wendy; Sprokholt, Joris K.; Clough, Barbara; Frickel, Eva-Maria; Saeij, Jeroen P. J.

    2013-01-01

    The intracellular protozoan parasite Toxoplasma gondii is a major food-borne illness and opportunistic infection for the immunosuppressed. Resistance to Toxoplasma is dependent on gamma interferon (IFN-γ) activation of both hematopoietic and nonhematopoietic cells. Although IFN-γ-induced innate

  15. Cell death of gamma interferon-stimulated human fibroblasts upon toxoplasma gondii infection induces early parasite egress and limits parasite replication

    NARCIS (Netherlands)

    Niedelman, W.; Sprokholt, J.K.; Clough, B.; Frickel, E.; Saeij, J.P.J.

    2013-01-01

    The intracellular protozoan parasite Toxoplasma gondii is a major food-borne illness and opportunistic infection for the immunosuppressed. Resistance to Toxoplasma is dependent on gamma interferon (IFN-¿) activation of both hematopoietic and nonhematopoietic cells. Although IFN-¿-induced innate

  16. Transcriptome Analysis of the Intracellular Facultative Pathogen Piscirickettsia salmonis: Expression of Putative Groups of Genes Associated with Virulence and Iron Metabolism.

    Directory of Open Access Journals (Sweden)

    Alvaro Machuca

    Full Text Available The intracellular facultative bacteria Piscirickettsia salmonis is one of the most important pathogens of the Chilean aquaculture. However, there is a lack of information regarding the whole genomic transcriptional response according to different extracellular environments. We used next generation sequencing (NGS of RNA (RNA-seq to study the whole transcriptome of an isolate of P. salmonis (FAVET-INBIOGEN using a cell line culture and a modified cell-free liquid medium, with or without iron supplementation. This was done in order to obtain information about the factors there are involved in virulence and iron acquisition. First, the isolate was grown in the Sf21 cell line; then, the bacteria were cultured into a cell-free liquid medium supplemented or not with iron. We identified in the transcriptome, genes associated with type IV secretion systems, genes related to flagellar structure assembly, several proteases and sigma factors, and genes related to the development of drug resistance. Additionally, we identified for the first time several iron-metabolism associated genes including at least two iron uptake pathways (ferrous iron and ferric iron uptake that are actually expressed in the different conditions analyzed. We further describe putative genes that are related with the use and storage of iron in the bacteria, which have not been previously described. Several sets of genes related to virulence were expressed in both the cell line and cell-free culture media (for example those related to flagellar structure; such as basal body, MS-ring, C-ring, proximal and distal rod, and filament, which may play roles in other basic processes rather than been restricted to virulence.

  17. Depletion of autophagy-related genes ATG3 and ATG5 in Tenebrio molitor leads to decreased survivability against an intracellular pathogen, Listeria monocytogenes.

    Science.gov (United States)

    Tindwa, Hamisi; Jo, Yong Hun; Patnaik, Bharat Bhusan; Noh, Mi Young; Kim, Dong Hyun; Kim, Iksoo; Han, Yeon Soo; Lee, Yong Seok; Lee, Bok Luel; Kim, Nam Jung

    2015-01-01

    Macroautophagy (autophagy) is an evolutionarily conserved catabolic process involved in physiological and developmental processes including cell survival, death, and innate immunity. Homologues of most of 36 originally discovered autophagy-related (ATG) genes in yeast have been characterized in higher eukaryotes including insects. In this study, the homologues of ATG3 (TmATG3) and ATG5 (TmATG5) were isolated from the coleopteran beetle, Tenebrio molitor by expressed sequence tag and RNAseq approaches. The cDNA of TmATG3 and TmATG5 comprise open-reading frame sizes of 963 and 792 bp encoding polypeptides of 320 and 263 amino acid residues, respectively. TmATG3 and TmATG5 mRNA are expressed in all developmental stages, and mainly in fat body and hemocytes of larvae. TmATG3 and TmATG5 showed an overall sequence identity of 58-95% to other insect Atg proteins. There exist clear one-to-one orthologs of TmATG3 and TmATG5 in Tribolium and that they clustered together in the gene tree. Depletion of TmATG3 and TmATG5 by RNA interference led to a significant reduction in survival ability of T. molitor larvae against an intracellular pathogen, Listeria monocytogenes. Six days post-Listeria challenge, the survival rate in the dsEGFP-injected (where EGFP is enhanced green fluorescent protein) control larvae was significantly higher (55%) compared to 4 and 3% for TmATG3 and TmATG5 double-stranded RNA injected larvae, respectively. These data suggested that TmATG3 and TmATG5 may play putative role in mediating autophagy-based clearance of Listeria in T. molitor model. © 2014 Wiley Periodicals, Inc.

  18. The Evolution of Host Mitochondrial Association and its Impact on Toxoplasma gondii Infection

    Science.gov (United States)

    English, Elizabeth D.

    The association of intracellular pathogens with host mitochondria has been observed across taxa, from bacterial pathogens, such as Legionella pneumophila and Chlamydia trachomati, to the eukaryotic pathogen Toxoplasma gondii. However the functional impact of host mitochondrial association (HMA) remains difficult to assess in most of these species because in many cases the genes responsible for this phenomenon have not yet been identified. The recent discovery of the T. gondii gene responsible for HMA, Mitochondrial Association Factor 1 ( MAF1) has provided us with the tools to begin to understand the evolution and impact of HMA. Here we use multispecies sequence analysis to determine that the MAF1 locus is tandemly duplicated and diversified in both T. gondii and its nearest extant relative Hammondia hammondi, but not another close relative Neospora caninum. Using cross-species complementation we find that T. gondii and H. hammondi harbor copies of MAF1 able to mediate HMA, while N. caninum does not. We have begun mutational analysis using naturally occurring HMA+ and HMA- paralogs of MAF1 in order to determine the portions of MAF1 protein necessary for HMA. Additionally, we have identified the first in vivo phenotypes associated with HMA using multiple mouse models, for both acute and chronic infection. Taken together these data indicate that HMA likely evolved via neofunctionalization of a duplicated ancestral MAF1 gene, and that the neofunctionalized, HMA competent copy of MAF1 provides a selective advantage.

  19. Seroprevalensi Toxoplasma gondii pada Kambing dan Bioassay Patogenitasnya pada Kucing

    Directory of Open Access Journals (Sweden)

    Ni Made Yunik Novita Dewi Dewi

    2013-11-01

    Full Text Available Normal 0 false false false EN-US X-NONE X-NONE The study aimed to determine seroprevalence of Toxoplasmosis in goats sloughtered at Kampung Jawa, Denpasar, Bali and to evaluate their pathogenicities through bioassay in cats.One hundred serums and meats of goats were collected. Anti-Toxoplasma gondii antibody was determined using Indirect Haemaglutination (IHA test. The pathogenicity bioassay of Toxoplasma gondii was carried out through inoculating the meats of goats which had seropositive of Toxoplasma gondii to the cats. The pathogenicity was evaluated using the intensity of oocyte sheding from the cats. The result showed that the seroprevalence of Toxoplasmosis was 46%. There was not significant difference between pathogenicity of Toxoplasma gondii in cat inoculated with meat of goat which had a high and low titer of antibody against Toxoplasma gondii. /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0in 5.4pt 0in 5.4pt; mso-para-margin:0in; mso-para-margin-bottom:.0001pt; text-align:justify; line-height:150%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin;}

  20. Induction of partial protection against infection with Toxoplasma gondii genotype II by DNA vaccination with recombinant chimeric tachyzoite antigens

    DEFF Research Database (Denmark)

    Rosenberg, Carina Agerbo; De Craeye, S.; Jongert, E.

    2009-01-01

    Infection with the obligate intracellular parasite Toxoplasma gondii is a significant source of parasitic infections worldwide. In adults, infections may often lead to severe retinochoroiditis. Infection of the foetus causes abortion or congenital pathology that may lead to neurological complicat......Infection with the obligate intracellular parasite Toxoplasma gondii is a significant source of parasitic infections worldwide. In adults, infections may often lead to severe retinochoroiditis. Infection of the foetus causes abortion or congenital pathology that may lead to neurological...

  1. Role of IL-12 and IFN-γ in immune response to toxoplasma gondii infection

    International Nuclear Information System (INIS)

    Moawad, M.A.F.; ElGawish, M.A.M.

    2004-01-01

    Interlenkin 12 (IL-12) is a potent immunoregulatory molecule that is critically involved in a wide range of diseases. In several murine models of intracellular infection, endogenous IL-12 has been shown to be crucial for the generation of a protective Th1 response in a primary infection for a intracellular pathogens. Interferon-gamma (IFN-γ) is also an important mediator of cellular immunity against microbial pathogens and tumor cells due to its potent capacity to activate macrophages for enhanced cytotoxicity. The aim of the present study is to evaluate the immune response to toxoplasma gondii after primary inflection (infected groups and secondary infection (re-infected groups for over 19 weeks (the time of the experiment). the evaluation was assessed by measurements of levels of IL-12 and IFN-γ using ELISA technique in the sera of these infected rats. The results demonstrated that the primary immune response induced a fluctuation in the levels of IL-12 in the sera of infected rats, which reached maximum value of 122.6 ±1.4 pg/ml after 15 weeks of primary infection. While, in the challenged groups (secondary immune response, re-infected groups) the levels of IL-12 were generally lower than that of the primary immune response. On the other hand, IFN-γ levels increased significantly in the secondary immune response (re-infected groups) as compared to primary immune response 9 infected groups) In conclusion, the results suggest that IL-12 might have a role in the defense mechanism against intracellular infection with T-gondii especially in primary immune response than in the secondary immune response. This is in contrast to IFN-γ that takes the up-hand in secondary immune response to T-gondii infection

  2. Toxoplasma gondii and schizophrenia

    OpenAIRE

    Mokhtari Mohammadreza; Mokhtari Mojgan

    2006-01-01

    Recent epidemiologic studies indicate that infectious agents may contribute to some cases of schizophrenia. In animals, infection with Toxoplasma gondii can alter behavior and neurotransmitter function. In humans, acute infection with T. gondii can produce psychotic symptoms similar to those displayed by persons with schizophrenia. Since 1953, a total of 19 studies of T. gondii antibodies in persons with schizophrenia and other severe psychiatric disorders and in controls have been reported; ...

  3. Forward genetic screening identifies a small molecule that blocks Toxoplasma gondii growth by inhibiting both host- and parasite-encoded kinases.

    Directory of Open Access Journals (Sweden)

    Kevin M Brown

    2014-06-01

    Full Text Available The simultaneous targeting of host and pathogen processes represents an untapped approach for the treatment of intracellular infections. Hypoxia-inducible factor-1 (HIF-1 is a host cell transcription factor that is activated by and required for the growth of the intracellular protozoan parasite Toxoplasma gondii at physiological oxygen levels. Parasite activation of HIF-1 is blocked by inhibiting the family of closely related Activin-Like Kinase (ALK host cell receptors ALK4, ALK5, and ALK7, which was determined in part by use of an ALK4,5,7 inhibitor named SB505124. Besides inhibiting HIF-1 activation, SB505124 also potently blocks parasite replication under normoxic conditions. To determine whether SB505124 inhibition of parasite growth was exclusively due to inhibition of ALK4,5,7 or because the drug inhibited a second kinase, SB505124-resistant parasites were isolated by chemical mutagenesis. Whole-genome sequencing of these mutants revealed mutations in the Toxoplasma MAP kinase, TgMAPK1. Allelic replacement of mutant TgMAPK1 alleles into wild-type parasites was sufficient to confer SB505124 resistance. SB505124 independently impacts TgMAPK1 and ALK4,5,7 signaling since drug resistant parasites could not activate HIF-1 in the presence of SB505124 or grow in HIF-1 deficient cells. In addition, TgMAPK1 kinase activity is inhibited by SB505124. Finally, mice treated with SB505124 had significantly lower tissue burdens following Toxoplasma infection. These data therefore identify SB505124 as a novel small molecule inhibitor that acts by inhibiting two distinct targets, host HIF-1 and TgMAPK1.

  4. Group 1 innate lymphoid cells in Toxoplasma gondii infection.

    Science.gov (United States)

    Dunay, I R; Diefenbach, A

    2018-02-01

    Innate lymphoid cells (ILCs) are a group of lymphocytes that carry out important functions in immunity to infections and in organ homeostasis at epithelial barrier surfaces. ILCs are innate immune cells that provide an early source of cytokines to initiate immune responses against pathogens. Cytotoxic ILCs (i.e. conventional (c)NK cells) and several subsets of helper-like ILCs are the major branches of the ILC family. Conventional NK cells and group 1 ILCs share several characteristics such as surface receptors and the ability to produce IFN-γ upon activation, but they differ in their developmental paths and in their dependence on specific transcription factors. Infection of mice with the intracellular parasite Toxoplasma gondii is followed by a strong Th1-mediated immune response. Previous studies indicate that NK1.1 + cells contribute to the production of IFN-γ and TNF and cytotoxicity during acute T. gondii infection. Upon oral infection, the parasite infects intestinal enterocytes, and within the lamina propria, innate immune responses lead to initial parasite control although the infection disseminates widely and persists long-term in immune privileged sites despite adaptive immunity. Upon parasite entry into the small intestine, during the acute stage, ILC1 produce high levels of IFN-γ and TNF protecting barrier surfaces, thus essentially contributing to early parasite control. We will discuss here the role of innate lymphocytes during T. gondii infection in the context of the only recently appreciated diversity of ILC subsets. © 2018 John Wiley & Sons Ltd.

  5. Adenosine metabolism in Toxoplasma gondii: potential targets for chemotherapy.

    Science.gov (United States)

    el Kouni, Mahmoud H

    2007-01-01

    Toxoplasma gondii is an intracellular parasitic protozoan that infects approximately a billion people worldwide. Infection with T. gondii represents a major health problem for immunocompromised individuals, such as AIDS patients, organ transplant recipients, and the unborn children of infected mothers. Currently available drugs usually do not eradicate infection and as many as 50% of the patients do not respond to this therapy. Furthermore, they are ineffective against T. gondii tissue cysts. In addition, prolonged exposure to these drugs induces serious host toxicity forcing the discontinuation of the therapy. Finally, there is no effective vaccine currently available for the treatment of toxoplasmosis. Therefore, it is necessary to develop new and effective drugs for the treatment and management of toxoplasmosis. The rational design of a drug depends on the exploitation of fundamental biochemical or physiological differences between pathogens and their host. Some of the most striking differences between T. gondii and their mammalian host are found in purine metabolism. T. gondii, like most parasites studied, lack the ability to synthesize purines do novo and depend on the salvage of purines from their host to satisfy their requirements of purines. In this respect, the salvage of adenosine is the major source of purines in T. gondii. Therefore, interference with adenosine uptake and metabolism in T. gondii can be selectively detrimental to the parasite. The host cells, on the other hand, can still obtain their purine requirements by their de novo pathways. This review will focus on the broad aspects of the adenosine transport and the enzyme adenosine kinase (EC 2.7.1.20) which are the two primary routes for adenosine utilization in T. gondii, in an attempt to illustrate their potentials as targets for chemotherapy against this parasite.

  6. Toxoplasma depends on lysosomal consumption of autophagosomes for persistent infection.

    Science.gov (United States)

    Di Cristina, Manlio; Dou, Zhicheng; Lunghi, Matteo; Kannan, Geetha; Huynh, My-Hang; McGovern, Olivia L; Schultz, Tracey L; Schultz, Aric J; Miller, Alyssa J; Hayes, Beth M; van der Linden, Wouter; Emiliani, Carla; Bogyo, Matthew; Besteiro, Sébastien; Coppens, Isabelle; Carruthers, Vern B

    2017-06-19

    Globally, nearly 2 billion people are infected with the intracellular protozoan Toxoplasma gondii 1 . This persistent infection can cause severe disease in immunocompromised people and is epidemiologically linked to major mental illnesses 2 and cognitive impairment 3 . There are currently no options for curing this infection. The lack of effective therapeutics is due partly to a poor understanding of the essential pathways that maintain long-term infection. Although it is known that Toxoplasma replicates slowly within intracellular cysts demarcated with a cyst wall, precisely how it sustains itself and remodels organelles in this niche is unknown. Here, we identify a key role for proteolysis within the parasite lysosomal organelle (the vacuolar compartment or VAC) in turnover of autophagosomes and persistence during neural infection. We found that disrupting a VAC-localized cysteine protease compromised VAC digestive function and markedly reduced chronic infection. Death of parasites lacking the VAC protease was preceded by accumulation of undigested autophagosomes in the parasite cytoplasm. These findings suggest an unanticipated function for parasite lysosomal degradation in chronic infection, and identify an intrinsic role for autophagy in the T. gondii parasite and its close relatives. This work also identifies a key element of Toxoplasma persistence and suggests that VAC proteolysis is a prospective target for pharmacological development.

  7. Serological Evidence of Toxoplasma gondii infection in five species of bats in China

    Science.gov (United States)

    Toxoplasma gondii is an obligate intracellular protozoan parasite which can infect almost all warm-blooded animals and humans with a worldwide distribution. Bats are reservoirs for an increasing number of emerging zoonotic viruses, such as henipaviruses and severe acute respiratory syndrome (SARS) c...

  8. SAG2 locus genotyping of Toxoplasma gondii in meat products of ...

    African Journals Online (AJOL)

    Toxoplasmosis is an infection caused by Toxoplasma gondii, an intracellular obligate parasite. Its transmission is usually attributed to ingestion of undercooked or raw meat. The aim of this study was the detection and genotyping of T. gondii in meat products using the molecular method in East Azerbaijan. DNA was ...

  9. Inflammasome sensor NLRP1 controls rat macrophage susceptibility to Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Kimberly M Cirelli

    2014-03-01

    Full Text Available Toxoplasma gondii is an intracellular parasite that infects a wide range of warm-blooded species. Rats vary in their susceptibility to this parasite. The Toxo1 locus conferring Toxoplasma resistance in rats was previously mapped to a region of chromosome 10 containing Nlrp1. This gene encodes an inflammasome sensor controlling macrophage sensitivity to anthrax lethal toxin (LT induced rapid cell death (pyroptosis. We show here that rat strain differences in Toxoplasma infected macrophage sensitivity to pyroptosis, IL-1β/IL-18 processing, and inhibition of parasite proliferation are perfectly correlated with NLRP1 sequence, while inversely correlated with sensitivity to anthrax LT-induced cell death. Using recombinant inbred rats, SNP analyses and whole transcriptome gene expression studies, we narrowed the candidate genes for control of Toxoplasma-mediated rat macrophage pyroptosis to four genes, one of which was Nlrp1. Knockdown of Nlrp1 in pyroptosis-sensitive macrophages resulted in higher parasite replication and protection from cell death. Reciprocally, overexpression of the NLRP1 variant from Toxoplasma-sensitive macrophages in pyroptosis-resistant cells led to sensitization of these resistant macrophages. Our findings reveal Toxoplasma as a novel activator of the NLRP1 inflammasome in rat macrophages.

  10. Toxoplasmosis (Toxoplasma infection) Disease Symptoms

    Science.gov (United States)

    ... Form Controls Cancel Submit Search the CDC Parasites - Toxoplasmosis (Toxoplasma infection) Note: Javascript is disabled or is ... message, please visit this page: About CDC.gov . Toxoplasmosis General Information Toxoplasmosis FAQs Toxoplasmosis & Pregnancy FAQs Epidemiology & ...

  11. Impaired chromatin remodelling at STAT1-regulated promoters leads to global unresponsiveness of Toxoplasma gondii-infected macrophages to IFN-γ.

    Directory of Open Access Journals (Sweden)

    Christine Lang

    2012-01-01

    Full Text Available Intracellular pathogens including the apicomplexan and opportunistic parasite Toxoplasma gondii profoundly modify their host cells in order to establish infection. We have shown previously that intracellular T. gondii inhibit up-regulation of regulatory and effector functions in murine macrophages (MΦ stimulated with interferon (IFN-γ, which is the cytokine crucial for controlling the parasites' replication. Using genome-wide transcriptome analysis we show herein that infection with T. gondii leads to global unresponsiveness of murine macrophages to IFN-γ. More than 61% and 89% of the transcripts, which were induced or repressed by IFN-γ in non-infected MΦ, respectively, were not altered after stimulation of T. gondii-infected cells with IFN-γ. These genes are involved in a variety of biological processes, which are mostly but not exclusively related to immune responses. Analyses of the underlying mechanisms revealed that IFN-γ-triggered nuclear translocation of STAT1 still occurred in Toxoplasma-infected MΦ. However, STAT1 bound aberrantly to oligonucleotides containing the IFN-γ-responsive gamma-activated site (GAS consensus sequence. Conversely, IFN-γ did not induce formation of active GAS-STAT1 complexes in nuclear extracts from infected MΦ. Mass spectrometry of protein complexes bound to GAS oligonucleotides showed that T. gondii-infected MΦ are unable to recruit non-muscle actin to IFN-γ-responsive DNA sequences, which appeared to be independent of stimulation with IFN-γ and of STAT1 binding. IFN-γ-induced recruitment of BRG-1 and acetylation of core histones at the IFN-γ-regulated CIITA promoter IV, but not β-actin was diminished by >90% in Toxoplasma-infected MΦ as compared to non-infected control cells. Remarkably, treatment with histone deacetylase inhibitors restored the ability of infected macrophages to express the IFN-γ regulated genes H2-A/E and CIITA. Taken together, these results indicate that Toxoplasma

  12. Comprehensive Evaluation of Toxoplasma gondii VEG and Neospora caninum LIV Genomes with Tachyzoite Stage Transcriptome and Proteome Defines Novel Transcript Features

    KAUST Repository

    Ramaprasad, Abhinay; Mourier, Tobias; Naeem, Raeece; Malas, Tareq B.; Moussa, Ehab; Panigrahi, Aswini; Vermont, Sarah J.; Otto, Thomas D.; Wastling, Jonathan; Pain, Arnab

    2015-01-01

    Toxoplasma gondii is an important protozoan parasite that infects all warm-blooded animals and causes opportunistic infections in immuno-compromised humans. Its closest relative, Neospora caninum, is an important veterinary pathogen that causes

  13. Non-coding RNA regulation in pathogenic bacteria located inside eukaryotic cells

    NARCIS (Netherlands)

    Ortega, Alvaro D.; Quereda, Juan J; Pucciarelli, M Graciela; García-del Portillo, Francisco

    2014-01-01

    Intracellular bacterial pathogens have evolved distinct lifestyles inside eukaryotic cells. Some pathogens coexist with the infected cell in an obligate intracellular state, whereas others transit between the extracellular and intracellular environment. Adaptation to these intracellular lifestyles

  14. Serological survey of antibodies to Toxoplasma gondii and Coxiella burnetii in rodents in north-western African islands (Canary Islands and Cape Verde).

    Science.gov (United States)

    Foronda, Pilar; Plata-Luis, Josué; del Castillo-Figueruelo, Borja; Fernández-Álvarez, Ángela; Martín-Alonso, Aarón; Feliu, Carlos; Cabral, Marilena D; Valladares, Basilio

    2015-05-29

    Coxiella burnetii and Toxoplasma gondii are intracellular parasites that cause important reproductive disorders in animals and humans worldwide, resulting in high economic losses. The aim of the present study was to analyse the possible role of peridomestic small mammals in the maintenance and transmission of C. burnetii and T. gondii in the north-western African archipelagos of the Canary Islands and Cape Verde, where these species are commonly found affecting humans and farm animals. Between 2009 and 2013, 108 black rats (Rattus rattus) and 77 mice (Mus musculus) were analysed for the presence of Coxiella and Toxoplasma antibodies by enzyme-linked immunosorbent assay (ELISA) and indirect immunofluorescence (IFA), respectively. Our results showed a wide distribution of C. burnetii and T. gondii, except for T. gondii in Cape Verde, in both rodent species. The overall seroprevalence of C. burnetii antibodies was 12.4%; 21.1% for Cape Verde and 10.2% for the Canary Islands. With respect to T. gondii, seropositive rodents were only observed in the Canary Islands, with an overall seroprevalence of 15%. Considering the fact that both pathogens can infect a large range of hosts, including livestock and humans, the results are of public health and veterinary importance and could be used by governmental entities to manage risk factors and to prevent future cases of Q fever and toxoplasmosis.

  15. [The seroprevalence of Toxoplasma gondii in women from Sanliurfa, a province with a high raw meatball consumption].

    Science.gov (United States)

    Tekay, Fikret; Ozbek, Erdal

    2007-01-01

    Toxoplasma gondii is an obligate intracellular protozoan that can infect all kind of birds and all mammals including humans and is common throughout the world. The prevalence varies according to social and cultural habits, pet cats in homes and geographic factors. Domestic cats are considered to be an important source of Toxoplasma gondii infection. From January to June 2006, the prevalence of toxoplasmosis was retrospectively monitored from blood samples that had been sent to our laboratory in order to determine the levels of IgM and IgG. All the subjects were women and 2,586 blood samples were investigated with the chemiluminescence immunoassay method. The rates of Toxoplasma gondii IgM antibodies were found to be 3.0% (78/2,586) and that of Toxoplasma gondii IgG antibodies, 69.5% (1.798/2,586). The total rate of positivity of Toxoplasma gondii antibodies was 69.6% (1,801/2,586) and the negativity, 30.4% (785/2,586). The highest positive rates have been reported in the southeastern region of Turkey and the 69.6% detected in our study seems to be the highest rate. Raw meatball consumption is common in our region and raw meat has a high risk of Toxoplasma gondii infection by direct ingestion of tissue cysts. As a result we consider that the high frequency of Toxoplasma gondii seropositivity in this region is due to raw meatball consumption.

  16. The Animal Pathogen-Like Type III Secretion System is Required for the Intracellular Survival of Burkholderia mallei within J774.2 Macrophages

    Science.gov (United States)

    2006-03-30

    for B. mallei are horses, donkeys, and mules (solipeds), but other animals, including mice, hamsters, guinea pigs, monkeys , lions, and dogs, are...Spa/Prg and Shigella Ipa/Mxi/Spa TTS networks, are important for in vitro and in vivo survival of these pathogenic Burkholderia species (9–12, 14, 15

  17. Disease resistance in Atlantic salmon (Salmo salar: coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

    Directory of Open Access Journals (Sweden)

    Jean Paul Lhorente

    Full Text Available BACKGROUND: Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1 coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2 coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. METHODOLOGY: In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI of P. salmonis (primary pathogen or coinfection with C. rogercresseyi (secondary pathogen. Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish. Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. MAIN FINDINGS: C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545. Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07. A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01 but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34. CONCLUSIONS/SIGNIFICANCE: C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future

  18. Disease resistance in Atlantic salmon (Salmo salar): coinfection of the intracellular bacterial pathogen Piscirickettsia salmonis and the sea louse Caligus rogercresseyi.

    Science.gov (United States)

    Lhorente, Jean Paul; Gallardo, José A; Villanueva, Beatriz; Carabaño, María J; Neira, Roberto

    2014-01-01

    Naturally occurring coinfections of pathogens have been reported in salmonids, but their consequences on disease resistance are unclear. We hypothesized that 1) coinfection of Caligus rogercresseyi reduces the resistance of Atlantic salmon to Piscirickettsia salmonis; and 2) coinfection resistance is a heritable trait that does not correlate with resistance to a single infection. In total, 1,634 pedigreed Atlantic salmon were exposed to a single infection (SI) of P. salmonis (primary pathogen) or coinfection with C. rogercresseyi (secondary pathogen). Low and high level of coinfection were evaluated (LC = 44 copepodites per fish; HC = 88 copepodites per fish). Survival and quantitative genetic analyses were performed to determine the resistance to the single infection and coinfections. C. rogercresseyi significantly increased the mortality in fish infected with P. salmonis (SI mortality = 251/545; LC mortality = 544/544 and HC mortality = 545/545). Heritability estimates for resistance to P. salmonis were similar and of medium magnitude in all treatments (h2SI = 0.23 ± 0.07; h2LC = 0.17 ± 0.08; h2HC = 0.24 ± 0.07). A large and significant genetic correlation with regard to resistance was observed between coinfection treatments (rg LC-HC = 0.99 ± 0.01) but not between the single and coinfection treatments (rg SI-LC = -0.14 ± 0.33; rg SI-HC = 0.32 ± 0.34). C. rogercresseyi, as a secondary pathogen, reduces the resistance of Atlantic salmon to the pathogen P. salmonis. Resistance to coinfection of Piscirickettsia salmonis and Caligus rogercresseyi in Atlantic salmon is a heritable trait. The absence of a genetic correlation between resistance to a single infection and resistance to coinfection indicates that different genes control these processes. Coinfection of different pathogens and resistance to coinfection needs to be considered in future research on salmon farming, selective breeding and conservation.

  19. Toxoplasma gondii GRA7-Targeted ASC and PLD1 Promote Antibacterial Host Defense via PKCα.

    Science.gov (United States)

    Koh, Hyun-Jung; Kim, Ye-Ram; Kim, Jae-Sung; Yun, Jin-Seung; Jang, Kiseok; Yang, Chul-Su

    2017-01-01

    Tuberculosis is a global health problem and at least one-third of the world's population is infected with Mycobacterium tuberculosis (MTB). MTB is a successful pathogen that enhances its own intracellular survival by inhibiting inflammation and arresting phago-lysosomal fusion. We previously demonstrated that Toxoplasma gondii (T. gondii) dense granule antigen (GRA) 7 interacts with TNF receptor-associated factor 6 via Myeloid differentiation primary response gene 88, enabling innate immune responses in macrophages. To extend these studies, we found that GRA7 interacts with host proteins involved in antimicrobial host defense mechanisms as a therapeutic strategy for tuberculosis. Here, we show that protein kinase C (PKC)α-mediated phosphorylation of T. gondii GRA7-I (Ser52) regulates the interaction of GRA7 with PYD domain of apoptosis-associated speck-like protein containing a carboxy-terminal CARD, which is capable of oligomerization and inflammasome activation can lead to antimicrobial defense against MTB. Furthermore, GRA7-III interacted with the PX domain of phospholipase D1, facilitating its enzyme activity, phago-lysosomal maturation, and subsequent antimicrobial activity in a GRA7-III (Ser135) phosphorylation-dependent manner via PKCα. Taken together, these results underscore a previously unrecognized role of GRA7 in modulating antimicrobial host defense mechanism during mycobacterial infection.

  20. Toxoplasma gondii GRA7-Targeted ASC and PLD1 Promote Antibacterial Host Defense via PKCα.

    Directory of Open Access Journals (Sweden)

    Hyun-Jung Koh

    2017-01-01

    Full Text Available Tuberculosis is a global health problem and at least one-third of the world's population is infected with Mycobacterium tuberculosis (MTB. MTB is a successful pathogen that enhances its own intracellular survival by inhibiting inflammation and arresting phago-lysosomal fusion. We previously demonstrated that Toxoplasma gondii (T. gondii dense granule antigen (GRA 7 interacts with TNF receptor-associated factor 6 via Myeloid differentiation primary response gene 88, enabling innate immune responses in macrophages. To extend these studies, we found that GRA7 interacts with host proteins involved in antimicrobial host defense mechanisms as a therapeutic strategy for tuberculosis. Here, we show that protein kinase C (PKCα-mediated phosphorylation of T. gondii GRA7-I (Ser52 regulates the interaction of GRA7 with PYD domain of apoptosis-associated speck-like protein containing a carboxy-terminal CARD, which is capable of oligomerization and inflammasome activation can lead to antimicrobial defense against MTB. Furthermore, GRA7-III interacted with the PX domain of phospholipase D1, facilitating its enzyme activity, phago-lysosomal maturation, and subsequent antimicrobial activity in a GRA7-III (Ser135 phosphorylation-dependent manner via PKCα. Taken together, these results underscore a previously unrecognized role of GRA7 in modulating antimicrobial host defense mechanism during mycobacterial infection.

  1. Seroprevalence of Toxoplasma gondii infection among pregnant women in Cameroon

    Directory of Open Access Journals (Sweden)

    Anna L. Njunda

    2011-09-01

    Full Text Available Toxoplasmosis is caused by an intracellular protozoan, Toxoplasma gondii, which has a wide geographical distribution. The congenital form results in a gestational form that can present a temporary parasiteamia that will infect the fetus. For this reason early diagnosis in pregnancy is highly desirable, allowing prompt intervention in cases of infection. The aim of this study was to determine the seroprevalence of Toxoplasma gondii antibodies among pregnant women attending the Douala General Hospital. The study was carried out between March and July 2009, whereby 110 pregnant women were tested for IgG and IgM antibodies and information about eating habits and hygienic conditions was collected using a questionnaire. These women’s ages ranged from 20-44 years old with an average of 29.9 years; the overall IgG and IgM seroprevalence was 70% and 2.73 % respectively. Seroprevalence was significantly high amongst women who ate raw vegetables (76.39%, P<0.05 and there was a significant trend towards a higher seroprevalence in women who did not have a good source of water (75.58%, P<0.05. This research showed that consumption raw vegetables and poor quality drinking water are two risk factors associated with Toxoplasma gondii infection amongst pregnant women attending the Douala General Hospital in Cameroon.

  2. Drug Repurposing Screening Identifies Novel Compounds That Effectively Inhibit Toxoplasma gondii Growth

    Science.gov (United States)

    Dittmar, Ashley J.; Drozda, Allison A.

    2016-01-01

    ABSTRACT The urgent need to develop new antimicrobial therapies has spawned the development of repurposing screens in which well-studied drugs and other types of compounds are tested for potential off-label uses. As a proof-of-principle screen to identify compounds effective against Toxoplasma gondii, we screened a collection of 1,120 compounds for the ability to significantly reduce Toxoplasma replication. A total of 94 compounds blocked parasite replication with 50% inhibitory concentrations of parasite invasion and replication but did so independently of inhibition of dopamine or other neurotransmitter receptor signaling. Tamoxifen, which is an established inhibitor of the estrogen receptor, also reduced parasite invasion and replication. Even though Toxoplasma can activate the estrogen receptor, tamoxifen inhibits parasite growth independently of this transcription factor. Tamoxifen is also a potent inducer of autophagy, and we find that the drug stimulates recruitment of the autophagy marker light chain 3-green fluorescent protein onto the membrane of the vacuolar compartment in which the parasite resides and replicates. In contrast to other antiparasitic drugs, including pimozide, tamoxifen treatment of infected cells leads to a time-dependent elimination of intracellular parasites. Taken together, these data suggest that tamoxifen restricts Toxoplasma growth by inducing xenophagy or autophagic destruction of this obligate intracellular parasite. IMPORTANCE There is an urgent need to develop new therapies to treat microbial infections, and the repurposing of well-characterized compounds is emerging as one approach to achieving this goal. Using the protozoan parasite Toxoplasma gondii, we screened a library of 1,120 compounds and identified several compounds with significant antiparasitic activities. Among these were pimozide and tamoxifen, which are well-characterized drugs prescribed to treat patients with psychiatric disorders and breast cancer

  3. A quantitative microbial risk assessment for meatborne Toxoplasma gondii infection in The Netherlands

    NARCIS (Netherlands)

    Opsteegh, M.; Prickaerts, S.; Frankena, K.; Evers, E.G.

    2011-01-01

    Toxoplasma gondii is an important foodborne pathogen, and the cause of a high disease burden due to congenital toxoplasmosis in The Netherlands. The aim of this study was to quantify the relative contribution of sheep, beef and pork products to human T. gondii infections by Quantitative Microbial

  4. Design of a Risk based Control System for Toxoplasma gondii in a pork supply chain

    NARCIS (Netherlands)

    Heres, L.; Swanenburg, M.; Koeijer, de A.A.; Boender, G.J.; Oorburg, D.; Urlings, B.; Wisselink, H.J.

    2015-01-01

    Toxoplasma gondii is recognized as one of the major foodborne pathogens. The European Food Safety Authority (EFSA) concluded that T. gondii is one of the public health hazards in pigs to be covered within a modern meat inspection and advised to include serological testing of pigs and audits of pig

  5. Isolation of Toxoplasma gondii in a pig from a local abattoir in ...

    African Journals Online (AJOL)

    Inoculation of pepsin digested muscle (mixed heart and diaphragm) from a slaughter pig into six Balb C mice resulted in the isolation of Toxoplasma gondii which proved to be pathogenic to mice. These infected mice were retarded in growth when compared to the two uninoculated control animals. Mouse No.3 and Mouse ...

  6. Kennel dogs as sentinels of Leishmania infantum, Toxoplasma gondii and Neospora caninum in Majorca Island, Spain

    Science.gov (United States)

    Kennel dogs can serve as sentinels and/or reservoirs of diseases of veterinary and zoonotic interest because they have often roamed free and lived outdoors, being exposed to pathogens. We tested for evidence of infection with three protozoans, Leishmania infantum, Toxoplasma gondii and Neospora cani...

  7. Toxoplasma gondii and Epilepsy.

    Science.gov (United States)

    Ayaz, Erol; Türkoğlu, Şule Aydın; Orallar, Hayriye

    2016-06-01

    Toxoplasma gondii is a zoonotic parasite can be seen in all the vital organ; in the acute phase, it can be found in the blood, cerebrospinal fluid, semen, tears, saliva, urine, and in almost all body fluids. Transplasental infection can lead to fetal damage and miscarriage. Its last hosts are felines and intermediate hosts are all mammals, including humans. People infected by the ingestion of meat containing cysts in undercooked or raw, are thrown oocysts with cat felines By taking in water and food, from mother to fetus transplacental way, the infected organ transplantation, blood transfusion, laboratory accidents and kaprofaj transmitted by mechanical vectors of the invertebrates. Suppression of the immune system is being transformed to the shape and texture of the cysts with bradyzoite. The parasite settles in the cells of the tissue cysts and causes change in the cellular mechanisms, such as cytokinin task. Depending on changes and type of neurotransmitter (GABA, glutamate, serotonin, dopamine) levels in CSF in ions (Ca, K, Cl, Mg), it is believed that there is a change in their concentration. In this review, literature about the relationship between T. gondii and epilepsy and epileptiform activity the importance of parasites, which settle in the brain, will be highlighted.

  8. Anti-N-methyl-D-aspartate receptor encephalitis associated with acute Toxoplasma gondii infection: A case report.

    Science.gov (United States)

    Cai, Xiaotang; Zhou, Hui; Xie, Yongmei; Yu, Dan; Wang, Zhiling; Ren, Haitao

    2018-02-01

    Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis has been recognized as the most frequent autoimmune encephalitis in children. Several infectious agents have been implicated in anti-NMDA encephalitis. A previously healthy immunocompetent 9-year-old girl first presented with seizures, headaches and vomiting. Cerebrospinal fluid and brain magnetic resonance imaging were normal. After one week onset, the patient gradually developed unexplained personality and behavior changes, accompanied by fever and seizures again. Repeated CSF analysis revealed a slightly lymphocytic predominant pleocytosis and positive anti-NMDAR antibody. A variety of pathogenic examinations were negative, except for positive toxoplasma IgM and IgG. The patient was diagnoses for anti-NMDA encephalitis associated with acute acquired toxoplasma gondii infection. The patient received 10 days azithromycin for treatment of acquired toxoplasma infection. The parents refuse immunotherapy because substantial recovery from clinical symptoms. The patient was substantially recovered with residual mild agitation after therapy for acquired toxoplasma gondii infection. Two months later, the patient was completely devoid of symptoms, and the levels of serum IgM and IgG of toxoplasma gondii were decreased. Acquired toxoplasma gondii infection may trigger anti-NMDAR encephalitis in children, which has not been reported previously. Clinicians should assess the possibility of toxoplasma gondii infection when evaluating a patient with anti-NMDA encephalitis.

  9. Latitudinal variability in the seroprevalence of antibodies against Toxoplasma gondii in non-migrant and Arctic migratory geese

    NARCIS (Netherlands)

    Sandstrom, Cecilia A. M.; Buma, Anita G. J.; Hoye, Bethany J.; Prop, Jouke; van der Jeugd, Henk; Voslamber, Berend; Madsen, Jesper; Loonen, Maarten J. J. E.

    2013-01-01

    Toxoplasma gondii is an intracellular coccidian parasite found worldwide and is known to infect virtually all warm-blooded animals. It requires a cat (family Felidae) to complete its full life cycle. Despite the absence of wild felids on the Arctic archipelago of Svalbard, T. gondii has been found

  10. 21 CFR 866.3780 - Toxoplasma gondii serological reagents.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Serological Reagents § 866.3780 Toxoplasma... (immunofluorescent reagents) used to identify Toxoplasma gondii from clinical specimens. The identification aids in...

  11. Epidemiology and Molecular Prevalence of Toxoplasma gondii in Cattle Slaughtered in Zahedan and Zabol Districts, South East of Iran

    Directory of Open Access Journals (Sweden)

    Davood ANVARI

    2018-03-01

    Full Text Available Background: Toxoplasma gondii is an obligate, intracellular parasite which causes the toxoplasmosis in humans and warm-blooded animals. Red meat is an important source for transmission of the infection to humans. This study aimed to determine the prevalence of Toxoplasma among imported and indigenous cattle in the Sistan region.Methods: One hundred samples from slaughtered cattle were collected from two abattoirs of Zabol and Zahedan, South East of Iran in 2015. Each sample was a mixture of three muscle, including tongue, cardiac, and triceps. Additional data of each cattle, including sex, breed, age, indigenous or imported, location of slaughter, management practices, and feeding system were obtained through observations and interviews. Infection by T. gondii was determined by PCR method.Results: The prevalence of Toxoplasma in indigenous cattle was 6% and in imported cattle was 26%, and this difference was statistically significant (P=0.006. Moreover, the prevalence of Toxoplasma was statistically associated with management practices (P=0.01 and feeding system (P=0.001. However, relationship between the prevalence of Toxoplasma with age, breed, sex, and location of slaughter was not statistically significant.Conclusion: Since the prevalence of Toxoplasma among imported cattle is higher than indigenous cattle, so strict supervision for importing livestock from neighboring countries is necessary.

  12. Toxoplasma gondii infection specifically increases the levels of key host microRNAs.

    Directory of Open Access Journals (Sweden)

    Gusti M Zeiner

    2010-01-01

    Full Text Available The apicomplexan parasite Toxoplasma gondii can infect and replicate in virtually any nucleated cell in many species of warm-blooded animals; thus, it has evolved the ability to exploit well-conserved biological processes common to its diverse hosts. Here we have investigated whether Toxoplasma modulates the levels of host microRNAs (miRNAs during infection.Using microarray profiling and a combination of conventional molecular approaches we report that Toxoplasma specifically modulates the expression of important host microRNAs during infection. We show that both the primary transcripts for miR-17 approximately 92 and miR-106b approximately 25 and the pivotal miRNAs that are derived from miR-17 approximately 92 display increased abundance in Toxoplasma-infected primary human cells; a Toxoplasma-dependent up-regulation of the miR-17 approximately 92 promoter is at least partly responsible for this increase. The abundance of mature miR-17 family members, which are derived from these two miRNA clusters, remains unchanged in host cells infected with the closely related apicomplexan Neospora caninum; thus, the Toxoplasma-induced increase in their abundance is a highly directed process rather than a general host response to infection.Altered levels of miR-17 approximately 92 and miR-106b approximately 25 are known to play crucial roles in mammalian cell regulation and have been implicated in numerous hyperproliferative diseases although the mechanisms driving their altered expression are unknown. Hence, in addition to the implications of these findings on the host-pathogen interaction, Toxoplasma may represent a powerful probe for understanding the normal mechanisms that regulate the levels of key host miRNAs.

  13. Molecular detection of Toxoplasma gondii in snakes.

    Science.gov (United States)

    Nasiri, Vahid; Teymurzadeh, Shohreh; Karimi, Gholamreza; Nasiri, Mehdi

    2016-10-01

    Toxoplasma gondii, an obligate intracellular protozoan parasite, is responsible for one of the most common zoonotic parasitic diseases in almost all warm-blooded vertebrates worldwide, and it is estimated that about one-third of the world human population is chronically infected with this parasite. Little is known about the circulation of T. gondii in snakes and this study for the first time aimed to evaluate the infection rates of snakes by this parasite by PCR methods. The brain of 68 Snakes, that were collected between May 2012 and September 2015 and died after the hold in captivity, under which they were kept for taking poisons, were examined for the presence of this parasite. DNA was extracted and Nested-PCR method was carried out with two of pairs of primers to detect the 344 bp fragment of T. gondii GRA6 gene. Five positive nested-PCR products were directly sequenced in the forward and reverse directions by Sequetech Company (Mountain View, CA). T. gondii GRA6 gene were detected from 55 (80.88%) of 68 snakes brains. Sequencing of the GRA6 gene revealed 98-100% of similarity with T. gondii sequences deposited in GenBank. To our knowledge, this is the first study of molecular detection of T. gondii in snakes and our findings show a higher frequency of this organism among them. Copyright © 2016 Elsevier Inc. All rights reserved.

  14. First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana) from Yucatan, Mexico

    OpenAIRE

    Torres-Castro, M.; Noh-Pech, H.; Puerto-Hern?ndez, R.; Reyes-Hern?ndez, B.; Panti-May, A.; Hern?ndez-Betancourt, S.; Yeh-Gorocica, A.; Gonz?lez-Herrera, L.; Zavala-Castro, J.; Puerto, F.I.

    2016-01-01

    Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13) in brains. Positive amplic...

  15. Foodborne pathogens

    Directory of Open Access Journals (Sweden)

    Thomas Bintsis

    2017-06-01

    Full Text Available Foodborne pathogens are causing a great number of diseases with significant effects on human health and economy. The characteristics of the most common pathogenic bacteria (Bacillus cereus, Campylobacter jejuni, Clostridium botulinum, Clostridium perfringens, Cronobacter sakazakii, Esherichia coli, Listeria monocytogenes, Salmonella spp., Shigella spp., Staphylococccus aureus, Vibrio spp. and Yersinia enterocolitica, viruses (Hepatitis A and Noroviruses and parasites (Cyclospora cayetanensis, Toxoplasma gondii and Trichinella spiralis, together with some important outbreaks, are reviewed. Food safety management systems based on to classical hazard-based approach has been proved to be inefficient, and risk-based food safety approach is now suggested from leading researchers and organizations. In this context, a food safety management system should be designed in a way to estimate the risks to human health from food consumption and to identify, select and implement mitigation strategies in order to control and reduce these risks. In addition, the application of suitable food safety education programs for all involved people in the production and consumption of foods is suggested.

  16. The association between foodborne and orofecal pathogens and allergic sensitisation -- EuroPrevall study

    NARCIS (Netherlands)

    Janse, Jacqueline J.; Wong, Gary W. K.; Potts, James; Ogorodova, Ludmila M.; Fedorova, Olga S.; Mahesh, P. A.; Sakellariou, Alexandros; Papadopoulos, Nikolaos G.; Knulst, André C.; Versteeg, Serge A.; Kroes, Aloys C. M.; Vossen, Ann C. T. M.; Campos Ponce, Maiza; Kummeling, Ischa; Burney, Peter; van Ree, Ronald; Yazdanbakhsh, Maria

    2014-01-01

    An inverse association between markers of exposure to foodborne and orofecal pathogens and allergic sensitization has been reported. However, the findings of epidemiological studies have not been consistent. This study investigated the relationship between antibodies to hepatitis A, Toxoplasma

  17. Toxoplasma gondii in small neotropical wild felids

    Directory of Open Access Journals (Sweden)

    William Alberto Cañon-Franco

    2013-02-01

    Full Text Available In the last decade, studies on wildlife worldwide have discovered key epidemiological aspects of the sylvatic cycle of Toxoplasma gondii. However, despite the known role of wild felines as definitive hosts in the transmission and maintenance of this parasite, few studies have focused on the involvement of these animals. Brazil exhibits the largest number of wild felid species in the Americas, all of which have a critical conservation status. However, serological detections, epidemiological studies and some molecular characterizations of T. gondii have primarily used Neotropical felid populations that are maintained in captivity, which does not reflect the disease behavior in free-living conditions. A systematic review of the worldwide scientific literature was conducted focusing on toxoplasmosis in small Neotropical felids. This review covered a number of aspects, including the state of scientific research, parasite transmission in the wild, the genetic characteristics of isolates, the relationship between these genetic characteristics and the pathogenicity of the parasite, and the risk factors linked to conflicts with humans. The present review shows the relevance of studying these felid populations based on their frequent interactions with humans in peri-urban areas and the need for further comprehensive studies to establish the real significance of T. gondii in public and animal health in tropical and temperate regions.

  18. Confocal microscope is able to detect calcium metabolic in neuronal infection by toxoplasma gondii

    International Nuclear Information System (INIS)

    Sensusiati, A D; Priya, T K S; Dachlan, Y P

    2017-01-01

    Calcium metabolism plays a very important role in neurons infected by Toxoplasma. Detection of change of calcium metabolism of neuron infected by Toxoplasma and Toxoplasma requires the calculation both quantitative and qualitative method. Confocal microscope has the ability to capture the wave of the fluorescent emission of the fluorescent dyes used in the measurement of cell calcium. The purpose of this study was to prove the difference in calcium changes between infected and uninfected neurons using confocal microscopy. Neuronal culture of human-skin-derived neural stem cell were divided into 6 groups, consisting 3 uninfected groups and 3 infected groups. Among the 3 groups were 2 hours, 24 hours and 48 hours. The neuron Toxoplasma gondii ratio was 1:5. Observation of intracellular calcium of neuron and tachyzoite, evidence of necrosis, apoptosis and the expression of Hsp 70 of neuron were examined by confocal microscope. The normality of the data was analysed by Kolmogorov-Smirnov Test, differentiation test was checked by t2 Test, and ANOVAs, for correlation test was done by Pearson Correlation Test. The calcium intensity of cytosolic neuron and T. gondii was significantly different from control groups (p<0.05). There was also significant correlation between calcium intensity with the evidence of necrosis and Hsp70 expression at 2 hours after infection. Apoptosis and necrosis were simultaneously shown with calcium contribution in this study. Confocal microscopy can be used to measure calcium changes in infected and uninfected neurons both in quantitatively and qualitatively. (paper)

  19. Confocal microscope is able to detect calcium metabolic in neuronal infection by toxoplasma gondii

    Science.gov (United States)

    Sensusiati, A. D.; Priya, T. K. S.; Dachlan, Y. P.

    2017-05-01

    Calcium metabolism plays a very important role in neurons infected by Toxoplasma. Detection of change of calcium metabolism of neuron infected by Toxoplasma and Toxoplasma requires the calculation both quantitative and qualitative method. Confocal microscope has the ability to capture the wave of the fluorescent emission of the fluorescent dyes used in the measurement of cell calcium. The purpose of this study was to prove the difference in calcium changes between infected and uninfected neurons using confocal microscopy. Neuronal culture of human-skin-derived neural stem cell were divided into 6 groups, consisting 3 uninfected groups and 3 infected groups. Among the 3 groups were 2 hours, 24 hours and 48 hours. The neuron Toxoplasma gondii ratio was 1:5. Observation of intracellular calcium of neuron and tachyzoite, evidence of necrosis, apoptosis and the expression of Hsp 70 of neuron were examined by confocal microscope. The normality of the data was analysed by Kolmogorov-Smirnov Test, differentiation test was checked by t2 Test, and ANOVAs, for correlation test was done by Pearson Correlation Test. The calcium intensity of cytosolic neuron and T. gondii was significantly different from control groups (pneurons both in quantitatively and qualitatively.

  20. Toxoplasma gondii peptide ligands open the gate of the HLA class I binding groove

    DEFF Research Database (Denmark)

    McMurtrey, Curtis; Trolle, Thomas; Sansom, Tiffany

    2016-01-01

    HLA class I presentation of pathogen-derived peptide ligands is essential for CD8+ T cell recognition of Toxoplasma gondii infected cells. Currently, little data exist pertaining to peptides that are presented after T. gondii infection. Herein we purify HLA-A*02:01 complexes from T. gondii infect...

  1. New Toxoplasma gondii genotypes isolated from free-range chickens from the Fernando de Noronha, Brazil: unexpected findings

    Science.gov (United States)

    Worldwide comparison of Toxoplasma gondii isolates from free range chickens has indicated that T. gondii isolates from Brazil are phenotypically and genetically different than isolates from other countries; most strains from Brazil are pathogenic to mice, there is great genetic variability, most iso...

  2. Seroprevalence of Toxoplasma gondii in free-living Amazon river dolphins (Inia geoffrensis) from central Amazon, Brazil

    Science.gov (United States)

    Toxoplasma gondii is an important pathogen in aquatic mammals and its presence in these animals may indicate water contamination of aquatic environment by oocysts. Serum samples from 95 dolphins from free-living Amazon River dolphins (Inia geoffrensis) from Sustainable Development Reserve Mamirauá (...

  3. toxoMine: an integrated omics data warehouse for Toxoplasma gondii systems biology research.

    Science.gov (United States)

    Rhee, David B; Croken, Matthew McKnight; Shieh, Kevin R; Sullivan, Julie; Micklem, Gos; Kim, Kami; Golden, Aaron

    2015-01-01

    Toxoplasma gondii (T. gondii) is an obligate intracellular parasite that must monitor for changes in the host environment and respond accordingly; however, it is still not fully known which genetic or epigenetic factors are involved in regulating virulence traits of T. gondii. There are on-going efforts to elucidate the mechanisms regulating the stage transition process via the application of high-throughput epigenomics, genomics and proteomics techniques. Given the range of experimental conditions and the typical yield from such high-throughput techniques, a new challenge arises: how to effectively collect, organize and disseminate the generated data for subsequent data analysis. Here, we describe toxoMine, which provides a powerful interface to support sophisticated integrative exploration of high-throughput experimental data and metadata, providing researchers with a more tractable means toward understanding how genetic and/or epigenetic factors play a coordinated role in determining pathogenicity of T. gondii. As a data warehouse, toxoMine allows integration of high-throughput data sets with public T. gondii data. toxoMine is also able to execute complex queries involving multiple data sets with straightforward user interaction. Furthermore, toxoMine allows users to define their own parameters during the search process that gives users near-limitless search and query capabilities. The interoperability feature also allows users to query and examine data available in other InterMine systems, which would effectively augment the search scope beyond what is available to toxoMine. toxoMine complements the major community database ToxoDB by providing a data warehouse that enables more extensive integrative studies for T. gondii. Given all these factors, we believe it will become an indispensable resource to the greater infectious disease research community. © The Author(s) 2015. Published by Oxford University Press.

  4. The transcriptome of Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Roos David S

    2005-12-01

    Full Text Available Abstract Background Toxoplasma gondii gives rise to toxoplasmosis, among the most prevalent parasitic diseases of animals and man. Transformation of the tachzyoite stage into the latent bradyzoite-cyst form underlies chronic disease and leads to a lifetime risk of recrudescence in individuals whose immune system becomes compromised. Given the importance of tissue cyst formation, there has been intensive focus on the development of methods to study bradyzoite differentiation, although the molecular basis for the developmental switch is still largely unknown. Results We have used serial analysis of gene expression (SAGE to define the Toxoplasma gondii transcriptome of the intermediate-host life cycle that leads to the formation of the bradyzoite/tissue cyst. A broad view of gene expression is provided by >4-fold coverage from nine distinct libraries (~300,000 SAGE tags representing key developmental transitions in primary parasite populations and in laboratory strains representing the three canonical genotypes. SAGE tags, and their corresponding mRNAs, were analyzed with respect to abundance, uniqueness, and antisense/sense polarity and chromosome distribution and developmental specificity. Conclusion This study demonstrates that phenotypic transitions during parasite development were marked by unique stage-specific mRNAs that accounted for 18% of the total SAGE tags and varied from 1–5% of the tags in each developmental stage. We have also found that Toxoplasma mRNA pools have a unique parasite-specific composition with 1 in 5 transcripts encoding Apicomplexa-specific genes functioning in parasite invasion and transmission. Developmentally co-regulated genes were dispersed across all Toxoplasma chromosomes, as were tags representing each abundance class, and a variety of biochemical pathways indicating that trans-acting mechanisms likely control gene expression in this parasite. We observed distinct similarities in the specificity and

  5. HLA-DQBl*0402 alleles polymorphisms detected in Javanese HIV patients with positive anti-Toxoplasma gondii IgM

    Science.gov (United States)

    Sari, Yulia; Haryati, Sri; Prasetyo, Afiono Agung; Hartono, Adnan, Zainal Arifin

    2017-02-01

    The human leukocyte antigen (HLA)-DQB1 gene polymorphisms may associated with the infection risk of Toxoplasma gondii in HIV patients. The HLA-DQB1*0402 in HIV-1-positive patients could be considered risk factors for developing neurological opportunistic infections, mainly Toxoplasma encephalitis. However, the HLA-DQB1*0402 gene polymorphisms status in the Javanese HIV patients is unknown. This study evaluated the prevalence of HLA-DQB*0402 alleles polymorphisms in Javanese HIV patients with positive anti-Toxoplasma gondii IgM status. Since 2009 our research group performing a molecular epidemiology of blood borne viruses in Central Java Indonesia, by collecting the epidemiological and clinical data from the high risk communities. All blood samples were screened for blood borne pathogens by serological and molecular assays including for HIV and Toxoplasma gondii. The genomic DNA was isolated from the whole blood samples. Genetic polymorphisms of HLA-DQB1*0402 alleles were detected with polymerase chain reaction-sequence-specific primers (PCR-SSPs) technique. The genotypes were defined according to generated fragment patterns in the agarose gel electrophoresis analysis of PCR products. All of the samples were tested at least in duplicate. HLA-DQB1*0402 alleles were detected in 20.8% (16/77) patients and not detected in all HIV positive samples with negative anti-Toxoplasma gondii IgM status (n= 200). The HLA-DQB1*0402 alleles polymorphisms were detected in Javanese HIV patients with positive anti-Toxoplasma gondii IgM. The polymorphisms found may have association with the infection risk of Toxoplasma gondii in HIV patients.

  6. Evasion of Human Neutrophil-Mediated Host Defense during Toxoplasma gondii Infection.

    Science.gov (United States)

    Lima, Tatiane S; Gov, Lanny; Lodoen, Melissa B

    2018-02-13

    Neutrophils are a major player in host immunity to infection; however, the mechanisms by which human neutrophils respond to the intracellular protozoan parasite Toxoplasma gondii are still poorly understood. In the current study, we found that, whereas primary human monocytes produced interleukin-1beta (IL-1β) in response to T. gondii infection, human neutrophils from the same blood donors did not. Moreover, T. gondii inhibited lipopolysaccharide (LPS)-induced IL-1β synthesis in human peripheral blood neutrophils. IL-1β suppression required active parasite invasion, since heat-killed or mycalolide B-treated parasites did not inhibit IL-1β release. By investigating the mechanisms involved in this process, we found that T. gondii infection of neutrophils treated with LPS resulted in reduced transcript levels of IL-1β and NLRP3 and reduced protein levels of pro-IL-1β, mature IL-1β, and the inflammasome sensor NLRP3. In T. gondii -infected neutrophils stimulated with LPS, the levels of MyD88, TRAF6, IKKα, IKKβ, and phosphorylated IKKα/β were not affected. However, LPS-induced IκBα degradation and p65 phosphorylation were reduced in T. gondii- infected neutrophils, and degradation of IκBα was reversed by treatment with the proteasome inhibitor MG-132. Finally, we observed that T. gondii inhibited the cleavage and activity of caspase-1 in human neutrophils. These results indicate that T. gondii suppression of IL-1β involves a two-pronged strategy whereby T. gondii inhibits both NF-κB signaling and activation of the NLRP3 inflammasome. These findings represent a novel mechanism of T. gondii evasion of human neutrophil-mediated host defense by targeting the production of IL-1β. IMPORTANCE Toxoplasma gondii is an obligate intracellular parasite that infects approximately one-third of humans worldwide and can invade virtually any nucleated cell in the human body. Although it is well documented that neutrophils infiltrate the site of acute T

  7. Cloning and expression of Toxoplasma gondii tachyzoite P22 protein

    African Journals Online (AJOL)

    Jane

    2011-08-01

    Aug 1, 2011 ... Expressd protein was purified by affinity chromatography and confirmed by western blot ... Key words: Toxoplasma gondii, cloning, recombinant P22. INTRODUCTION. Toxoplasma gondii ..... an ELISA Assay. Iran. J. Immunol.

  8. Veterinary vaccines against Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Elisabeth A Innes

    2009-03-01

    Full Text Available Toxoplasma gondii has a very wide intermediate host range and is thought to be able to infect all warm blooded animals. The parasite causes a spectrum of different diseases and clinical symptoms within the intermediate hosts and following infection most animals develop adaptive humoral and cell-mediated immune responses. The development of protective immunity to T. gondii following natural infection in many host species has led researchers to look at vaccination as a strategy to control disease, parasite multiplication and establishment in animal hosts. A range of different veterinary vaccines are required to help control T. gondii infection which include vaccines to prevent congenital toxoplasmosis, reduce or eliminate tissue cysts in meat producing animals and to prevent oocyst shedding in cats. In this paper we will discuss some of the history, challenges and progress in the development of veterinary vaccines against T. gondii.

  9. Fatal Toxoplasma gondii infection in the giant panda.

    Science.gov (United States)

    Ma, Hongyu; Wang, Zedong; Wang, Chengdong; Li, Caiwu; Wei, Feng; Liu, Quan

    2015-01-01

    Toxoplasma gondii can infect nearly all warm-blooded animals. We report an acute fatal T. gondii infection in the endangered giant panda (Ailuropoda melanoleuca) in a zoo in China, characterized by acute gastroenteritis and respiratory symptoms. T. gondii infection was confirmed by immunological and molecular methods. Multilocus nested PCR-RFLP revealed clonal type I at the SAG1 and c29-2 loci, clonal type II at the SAG2, BTUB, GRA6, c22-8, and L358 loci, and clonal type III at the alternative SAG2 and SAG3 loci, thus, a potential new genotype of T. gondii in the giant panda. Other possible pathogens were not detected. To our knowledge, this is the first report of clinical toxoplasmosis in a giant panda. © H. Ma et al., published by EDP Sciences, 2015.

  10. Fatal Toxoplasma gondii infection in the giant panda

    Directory of Open Access Journals (Sweden)

    2015-01-01

    Full Text Available Toxoplasma gondii can infect nearly all warm-blooded animals. We report an acute fatal T. gondii infection in the endangered giant panda (Ailuropoda melanoleuca in a zoo in China, characterized by acute gastroenteritis and respiratory symptoms. T. gondii infection was confirmed by immunological and molecular methods. Multilocus nested PCR-RFLP revealed clonal type I at the SAG1 and c29-2 loci, clonal type II at the SAG2, BTUB, GRA6, c22-8, and L358 loci, and clonal type III at the alternative SAG2 and SAG3 loci, thus, a potential new genotype of T. gondii in the giant panda. Other possible pathogens were not detected. To our knowledge, this is the first report of clinical toxoplasmosis in a giant panda.

  11. Toxoplasma gondii acetyl-CoA synthetase is involved in fatty acid elongation (of long fatty acid chains) during tachyzoite life stages.

    Science.gov (United States)

    Dubois, David; Fernandes, Stella; Amiar, Souad; Dass, Sheena; Katris, Nicholas J; Botté, Cyrille Y; Yamaryo-Botté, Yoshiki

    2018-06-01

    Apicomplexan parasites are pathogens responsible for major human diseases such as toxoplasmosis caused by Toxoplasma gondii and malaria caused by Plasmodium spp. Throughout their intracellular division cycle, the parasites require vast and specific amounts of lipids to divide and survive. This demand for lipids relies on a fine balance between de novo synthesized lipids and scavenged lipids from the host. Acetyl-CoA is a major and central precursor for many metabolic pathways, especially for lipid biosynthesis. T. gondii possesses a single cytosolic acetyl-CoA synthetase ( Tg ACS). Its role in the parasite lipid synthesis is unclear. Here, we generated an inducible Tg ACS KO parasite line and confirmed the cytosolic localization of the protein. We conducted 13 C-stable isotope labeling combined with mass spectrometry-based lipidomic analyses to unravel its putative role in the parasite lipid synthesis pathway. We show that its disruption has a minor effect on the global FA composition due to the metabolic changes induced to compensate for its loss. However, we could demonstrate that Tg ACS is involved in providing acetyl-CoA for the essential fatty elongation pathway to generate FAs used for membrane biogenesis. This work provides novel metabolic insight to decipher the complex lipid synthesis in T. gondii . Copyright © 2018 by the American Society for Biochemistry and Molecular Biology, Inc.

  12. Brains and Brawn: Toxoplasma Infections of the Central Nervous System and Skeletal Muscle.

    Science.gov (United States)

    Wohlfert, Elizabeth A; Blader, Ira J; Wilson, Emma H

    2017-07-01

    Toxoplasma gondii is a widespread parasitic pathogen that infects over a third of the world's population. Following an acute infection, the parasite can persist within its mammalian host as intraneuronal or intramuscular cysts. Cysts will occasionally reactivate, and - depending on the host's immune status and site of reactivation - encephalitis or myositis can develop. Because these diseases have high levels of morbidity and can be lethal, it is important to understand how Toxoplasma traffics to these tissues, how the immune response controls parasite burden and contributes to tissue damage, and what mechanisms underlie neurological and muscular pathologies that toxoplasmosis patients present with. This review aims to summarize recent important developments addressing these critical topics. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Toxoplasma gondii Actively Inhibits Neuronal Function in Chronically Infected Mice

    Science.gov (United States)

    Haroon, Fahad; Händel, Ulrike; Angenstein, Frank; Goldschmidt, Jürgen; Kreutzmann, Peter; Lison, Holger; Fischer, Klaus-Dieter; Scheich, Henning; Wetzel, Wolfram; Schlüter, Dirk; Budinger, Eike

    2012-01-01

    Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii–infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca2+) imaging studies revealed that tachyzoites actively manipulated Ca2+ signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca2+ uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca2+ stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host. PMID:22530040

  14. Toxoplasma gondii actively inhibits neuronal function in chronically infected mice.

    Directory of Open Access Journals (Sweden)

    Fahad Haroon

    Full Text Available Upon infection with the obligate intracellular parasite Toxoplasma gondii, fast replicating tachyzoites infect a broad spectrum of host cells including neurons. Under the pressure of the immune response, tachyzoites convert into slow-replicating bradyzoites, which persist as cysts in neurons. Currently, it is unclear whether T. gondii alters the functional activity of neurons, which may contribute to altered behaviour of T. gondii-infected mice and men. In the present study we demonstrate that upon oral infection with T. gondii cysts, chronically infected BALB/c mice lost over time their natural fear against cat urine which was paralleled by the persistence of the parasite in brain regions affecting behaviour and odor perception. Detailed immunohistochemistry showed that in infected neurons not only parasitic cysts but also the host cell cytoplasm and some axons stained positive for Toxoplasma antigen suggesting that parasitic proteins might directly interfere with neuronal function. In fact, in vitro live cell calcium (Ca(2+ imaging studies revealed that tachyzoites actively manipulated Ca(2+ signalling upon glutamate stimulation leading either to hyper- or hypo-responsive neurons. Experiments with the endoplasmatic reticulum Ca(2+ uptake inhibitor thapsigargin indicate that tachyzoites deplete Ca(2+ stores in the endoplasmatic reticulum. Furthermore in vivo studies revealed that the activity-dependent uptake of the potassium analogue thallium was reduced in cyst harbouring neurons indicating their functional impairment. The percentage of non-functional neurons increased over time In conclusion, both bradyzoites and tachyzoites functionally silence infected neurons, which may significantly contribute to the altered behaviour of the host.

  15. Exosome function: from tumor immunology to pathogen biology.

    Science.gov (United States)

    Schorey, Jeffrey S; Bhatnagar, Sanchita

    2008-06-01

    Exosomes are the newest family member of 'bioactive vesicles' that function to promote intercellular communication. Exosomes are derived from the fusion of multivesicular bodies with the plasma membrane and extracellular release of the intraluminal vesicles. Recent studies have focused on the biogenesis and composition of exosomes as well as regulation of exosome release. Exosomes have been shown to be released by cells of hematopoietic and non-hematopoietic origin, yet their function remains enigmatic. Much of the prior work has focused on exosomes as a source of tumor antigens and in presentation of tumor antigens to T cells. However, new studies have shown that exosomes might also promote cell-to-cell spread of infectious agents. Moreover, exosomes isolated from cells infected with various intracellular pathogens, including Mycobacterium tuberculosis and Toxoplasma gondii, have been shown to contain microbial components and can promote antigen presentation and macrophage activation, suggesting that exosomes may function in immune surveillance. In this review, we summarize our understanding of exosome biogenesis but focus primarily on new insights into exosome function. We also discuss their possible use as disease biomarkers and vaccine candidates.

  16. EVIDENCE FOR THE MACROPHAGE INDUCING GENE IN MYCOBACTERIUM INTRACELLULARE

    Science.gov (United States)

    Background: The Mycobacterium avium Complex (MAC) includes the species M. avium (MA), M. intracellulare (MI), and possibly others. Organisms belonging to the MAC are phylogenetically closely related, opportunistic pathogens. The macrophage inducing gene (mig) is the only well-des...

  17. Toxoplasma gondii infection shifts dendritic cells into an amoeboid rapid migration mode encompassing podosome dissolution, secretion of TIMP-1, and reduced proteolysis of extracellular matrix.

    Science.gov (United States)

    Ólafsson, Einar B; Varas-Godoy, Manuel; Barragan, Antonio

    2018-03-01

    Dendritic cells (DCs) infected by Toxoplasma gondii rapidly acquire a hypermigratory phenotype that promotes systemic parasite dissemination by a "Trojan horse" mechanism in mice. Recent paradigms of leukocyte migration have identified the amoeboid migration mode of DCs as particularly suited for rapid locomotion in extracellular matrix and tissues. Here, we have developed a microscopy-based high-throughput approach to assess motility and matrix degradation by Toxoplasma-challenged murine and human DCs. DCs challenged with T. gondii exhibited dependency on metalloproteinase activity for hypermotility and transmigration but, strikingly, also dramatically reduced pericellular proteolysis. Toxoplasma-challenged DCs up-regulated expression and secretion of tissue inhibitor of metalloproteinases-1 (TIMP-1) and their supernatants impaired matrix degradation by naïve DCs and by-stander DCs dose dependently. Gene silencing of TIMP-1 by short hairpin RNA restored matrix degradation activity in Toxoplasma-infected DCs. Additionally, dissolution of podosome structures in parasitised DCs coincided with abrogated matrix degradation. Toxoplasma lysates inhibited pericellular proteolysis in a MyD88-dependent fashion whereas abrogated proteolysis persevered in Toxoplasma-infected MyD88-deficient DCs. This indicated that both TLR/MyD88-dependent and TLR/MyD88-independent signalling pathways mediated podosome dissolution and the abrogated matrix degradation. We report that increased TIMP-1 secretion and cytoskeletal rearrangements encompassing podosome dissolution are features of Toxoplasma-induced hypermigration of DCs with an impact on matrix degradation. Jointly, the data highlight how an obligate intracellular parasite orchestrates key regulatory cellular processes consistent with non-proteolytic amoeboid migration of the vehicle cells that facilitate its dissemination. © 2017 John Wiley & Sons Ltd.

  18. Low prevalence of Neospora caninum and Toxoplasma gondii antibodies in dogs in Jilin, Henan and Anhui Provinces of the People’s Republic of China

    Science.gov (United States)

    Background: Neospora caninum and Toxoplasma gondii are important pathogens of worldwide distribution. N. caninum is a major cause of abortion in cattle and dogs are main reservoirs because they excrete the environmentally resistant oocysts. Toxoplasmosis is a worldwide zoonosis and dogs are consider...

  19. Seroprevalence of Toxoplasma gondii and concurrent bartonella spp., feline immunodeficiency virus, and feline leukemia infections in cats from Grenada, West Indies

    Science.gov (United States)

    Toxoplasma gondii and Bartonella spp. are zoonotic pathogens of cats. Feline Immunodeficiency Virus (FIV), and Feline Leukemia Virus (FeLv) are related to Human Iimmunodeficiency Virus, and Human Leukemia Virus, respectively, and these viruses are immunosuppressive. In the present study, the prevale...

  20. High prevalence of Toxoplasma gondii infection in Ethiopian cats in Addis Ababa, coinfection, and a review of toxoplasmosis in humans and other animals in Ethiopia

    Science.gov (United States)

    Toxoplasma gondii and Bartonella spp. are zoonotic pathogens of cats. Feline Immunodeficiency Virus (FIV), and Feline Leukemia Virus (FeLv) are related to Human Immunodeficiency Virus, and Human T-lymphotrophic Virus, respectively, and these viruses are immunosuppressive. In the present study, the p...

  1. Isolation and genetic characterization of Toxoplasma gondii from black bears (Ursus americanus), bobcats (Felis rufus), and feral cats (Felis catus) from Pennsylvania

    Science.gov (United States)

    Toxoplasma gondii infects virtually all warm-blooded hosts worldwide. Recently, attention has been focused on the genetic diversity of the parasite to explain its pathogenicity in different hosts. It has been hypothesized that interaction between feral and domestic cycles of T. gondii may increase u...

  2. Evaluating Recombinant Antigen ROP1 Efficacy in Diagnosis of Toxoplasma Gondii Infection

    Directory of Open Access Journals (Sweden)

    F Keshavarzi

    2015-07-01

    Full Text Available Introduction:Toxoplasma gondii is a ubiquitous obligate intracellular parasite with a relatively broad host range infecting both mammals and birds. Toxoplasma proteins are strong antigens that can begin strong immune reactions, among which Rhoptry protein 1 (ROP1 can be named discharging from rhoptry cell-organ. ROP1 is regarded as a competitor for recombinant vaccines against toxoplasmosis. Therefore, the main objective of the current study was to evaluate the cloning and expression of ROP1 Toxoplasma gondii in a cloning vector as well as to create this recombinant antigen in order to be applied for later uses. Methods:Genomic DNA of Toxoplasma gondii was removed and reproduced by PCR, then the PCR product was cloned into the EcoR1 and BamH1 sites of cloning vector, pUET1, and transformed into Escherichia coli BL21 plysS strain. Moreover, pcROP1 was sub-cloned into the HindIII and EcoRI sites of the pcDNA3 in order to produce recombining eukaryotic declaration vector. The cloned ROP1 was verified by PCR, limitation enzymes (HindIII and BglΙ digestion and nucleotide sequencing. Then, this recombinant antigen was covered applying IgM and ELISAIgG. Results:The study results demonstrated that a fragment of 757 bp was separated. In addition, nucleotide sequence analysis of the ROP1 cloned in pUET1vector revealed high homology (96% with RH strain Gene Bank Accession (No. M71274. Conclusion:The recombinant ROP1 antigen in an IgM Rec-ELISA test can be replaced with the tachyzoite antigen in IgG and IgM serologic tests.

  3. The crystal structure of Toxoplasma gondii pyruvate kinase 1.

    Directory of Open Access Journals (Sweden)

    Rebecca Bakszt

    2010-09-01

    Full Text Available Pyruvate kinase (PK, which catalyzes the final step in glycolysis converting phosphoenolpyruvate to pyruvate, is a central metabolic regulator in most organisms. Consequently PK represents an attractive therapeutic target in cancer and human pathogens, like Apicomplexans. The phylum Aplicomplexa, a group of exclusively parasitic organisms, includes the genera Plasmodium, Cryptosporidium and Toxoplasma, the etiological agents of malaria, cryptosporidiosis and toxoplasmosis respectively. Toxoplasma gondii infection causes a mild illness and is a very common infection affecting nearly one third of the world's population.We have determined the crystal structure of the PK1 enzyme from T. gondii, with the B domain in the open and closed conformations. We have also characterized its enzymatic activity and confirmed glucose-6-phosphate as its allosteric activator. This is the first description of a PK enzyme in a closed inactive conformation without any bound substrate. Comparison of the two tetrameric TgPK1 structures indicates a reorientation of the monomers with a concomitant change in the buried surface among adjacent monomers. The change in the buried surface was associated with significant B domain movements in one of the interacting monomers.We hypothesize that a loop in the interface between the A and B domains plays an important role linking the position of the B domain to the buried surface among monomers through two α-helices. The proposed model links the catalytic cycle of the enzyme with its domain movements and highlights the contribution of the interface between adjacent subunits. In addition, an unusual ordered conformation was observed in one of the allosteric binding domains and it is related to a specific apicomplexan insertion. The sequence and structural particularity would explain the atypical activation by a mono-phosphorylated sugar. The sum of peculiarities raises this enzyme as an emerging target for drug discovery.

  4. The crystal structure of Toxoplasma gondii pyruvate kinase 1.

    Science.gov (United States)

    Bakszt, Rebecca; Wernimont, Amy; Allali-Hassani, Abdellah; Mok, Man Wai; Hills, Tanya; Hui, Raymond; Pizarro, Juan C

    2010-09-14

    Pyruvate kinase (PK), which catalyzes the final step in glycolysis converting phosphoenolpyruvate to pyruvate, is a central metabolic regulator in most organisms. Consequently PK represents an attractive therapeutic target in cancer and human pathogens, like Apicomplexans. The phylum Aplicomplexa, a group of exclusively parasitic organisms, includes the genera Plasmodium, Cryptosporidium and Toxoplasma, the etiological agents of malaria, cryptosporidiosis and toxoplasmosis respectively. Toxoplasma gondii infection causes a mild illness and is a very common infection affecting nearly one third of the world's population. We have determined the crystal structure of the PK1 enzyme from T. gondii, with the B domain in the open and closed conformations. We have also characterized its enzymatic activity and confirmed glucose-6-phosphate as its allosteric activator. This is the first description of a PK enzyme in a closed inactive conformation without any bound substrate. Comparison of the two tetrameric TgPK1 structures indicates a reorientation of the monomers with a concomitant change in the buried surface among adjacent monomers. The change in the buried surface was associated with significant B domain movements in one of the interacting monomers. We hypothesize that a loop in the interface between the A and B domains plays an important role linking the position of the B domain to the buried surface among monomers through two α-helices. The proposed model links the catalytic cycle of the enzyme with its domain movements and highlights the contribution of the interface between adjacent subunits. In addition, an unusual ordered conformation was observed in one of the allosteric binding domains and it is related to a specific apicomplexan insertion. The sequence and structural particularity would explain the atypical activation by a mono-phosphorylated sugar. The sum of peculiarities raises this enzyme as an emerging target for drug discovery.

  5. The Crystal Structure of Toxoplasma gondii Pyruvate Kinase 1

    Energy Technology Data Exchange (ETDEWEB)

    Bakszt, R.; Wernimont, A; Allali-Hassani, A; Mok, M; Hills, T; Hui, R; Pizarro, J

    2010-01-01

    Pyruvate kinase (PK), which catalyzes the final step in glycolysis converting phosphoenolpyruvate to pyruvate, is a central metabolic regulator in most organisms. Consequently PK represents an attractive therapeutic target in cancer and human pathogens, like Apicomplexans. The phylum Aplicomplexa, a group of exclusively parasitic organisms, includes the genera Plasmodium, Cryptosporidium and Toxoplasma, the etiological agents of malaria, cryptosporidiosis and toxoplasmosis respectively. Toxoplasma gondii infection causes a mild illness and is a very common infection affecting nearly one third of the world's population. We have determined the crystal structure of the PK1 enzyme from T. gondii, with the B domain in the open and closed conformations. We have also characterized its enzymatic activity and confirmed glucose-6-phosphate as its allosteric activator. This is the first description of a PK enzyme in a closed inactive conformation without any bound substrate. Comparison of the two tetrameric TgPK1 structures indicates a reorientation of the monomers with a concomitant change in the buried surface among adjacent monomers. The change in the buried surface was associated with significant B domain movements in one of the interacting monomers. We hypothesize that a loop in the interface between the A and B domains plays an important role linking the position of the B domain to the buried surface among monomers through two {alpha}-helices. The proposed model links the catalytic cycle of the enzyme with its domain movements and highlights the contribution of the interface between adjacent subunits. In addition, an unusual ordered conformation was observed in one of the allosteric binding domains and it is related to a specific apicomplexan insertion. The sequence and structural particularity would explain the atypical activation by a mono-phosphorylated sugar. The sum of peculiarities raises this enzyme as an emerging target for drug discovery.

  6. Seroprevalence of Toxoplasma gondii infection amongst residents ...

    African Journals Online (AJOL)

    Toxoplasmosis is a zoonotic disease, recognized as a serious public health problem worldwide. Toxoplasma gondii infection has become a major public health concern in recent years due to the ravaging HIV/AIDS pandemic. A serological survey was carried out in Tanga district of north-eastern Tanzania to assess T. gondii ...

  7. Seroprevalence of Toxoplasma gondii and Neospora caninum ...

    African Journals Online (AJOL)

    The aim of this study was to compare the seroprevalence of Toxoplasma gondii and Neospora caninum in goats from two Argentinean provinces raised under different management conditions. A total of 2922 serum samples from adult goats of Córdoba (n=2187) and Buenos Aires provinces (n= 735), Argentina, were ...

  8. Mechanics of the Toxoplasma gondii oocyst wall

    Science.gov (United States)

    The ability of microorganisms to survive under extreme conditions is closely related to the physicochemical properties of their wall. In the ubiquitous protozoan parasite Toxoplasma gondii, the oocyst stage possesses a bilayered wall that protects the dormant but potentially infective parasites from...

  9. Toxoplasma-safe meat: close to reality?

    NARCIS (Netherlands)

    Kijlstra, A.; Jongert, E.

    2009-01-01

    In 2008, the centennial of the discovery of Toxoplasma gondii was celebrated. However, toxoplasmosis is still seen as a neglected and underreported disease, despite having a disease burden similar to that of salmonellosis and campylobacteriosis. Human vaccines are not available and current

  10. A novel multifunctional oligonucleotide microarray for Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Chen Feng

    2010-10-01

    Full Text Available Abstract Background Microarrays are invaluable tools for genome interrogation, SNP detection, and expression analysis, among other applications. Such broad capabilities would be of value to many pathogen research communities, although the development and use of genome-scale microarrays is often a costly undertaking. Therefore, effective methods for reducing unnecessary probes while maintaining or expanding functionality would be relevant to many investigators. Results Taking advantage of available genome sequences and annotation for Toxoplasma gondii (a pathogenic parasite responsible for illness in immunocompromised individuals and Plasmodium falciparum (a related parasite responsible for severe human malaria, we designed a single oligonucleotide microarray capable of supporting a wide range of applications at relatively low cost, including genome-wide expression profiling for Toxoplasma, and single-nucleotide polymorphism (SNP-based genotyping of both T. gondii and P. falciparum. Expression profiling of the three clonotypic lineages dominating T. gondii populations in North America and Europe provides a first comprehensive view of the parasite transcriptome, revealing that ~49% of all annotated genes are expressed in parasite tachyzoites (the acutely lytic stage responsible for pathogenesis and 26% of genes are differentially expressed among strains. A novel design utilizing few probes provided high confidence genotyping, used here to resolve recombination points in the clonal progeny of sexual crosses. Recent sequencing of additional T. gondii isolates identifies >620 K new SNPs, including ~11 K that intersect with expression profiling probes, yielding additional markers for genotyping studies, and further validating the utility of a combined expression profiling/genotyping array design. Additional applications facilitating SNP and transcript discovery, alternative statistical methods for quantifying gene expression, etc. are also pursued at

  11. Serosurvey of Leptospira spp. and Toxoplasma gondii in rats captured from two zoos in Southern Brazil.

    Science.gov (United States)

    Pellizzaro, Maysa; Conrado, Francisco de Oliveira; Martins, Camila Marinelli; Joaquim, Sâmea Fernandes; Ferreira, Fernando; Langoni, Helio; Biondo, Alexander Welker

    2017-01-01

    Norway rats (Rattus norvegicus) are zoonotic reservoirs for Leptospira spp. and Toxoplasma gondii, and influence diseases in urban areas. Free-ranging and laboratory-raised rats from two zoos in southern Brazil were tested for Leptospira spp. and T. gondii using microscopic agglutination and modified agglutination tests, respectively. Overall, 25.6% and 4.6% free-ranging rats tested positive for Leptospira spp. and T. gondii, respectively, with co-seropositivity occurring in two animals. For laboratory-raised rats, 20% tested positive for Leptospira spp. Also, Leptospira biflexa serovar Patoc and Leptospira noguchii serovar Panama were found. Serosurveys can show the environmental prevalence of zoonotic pathogens.

  12. The neurotropic parasite Toxoplasma gondii increases dopamine metabolism.

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    Emese Prandovszky

    Full Text Available The highly prevalent parasite Toxoplasma gondii manipulates its host's 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 parasite's 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 staining of encysted parasites. Based on these analyses, T. gondii orchestrates a significant increase in dopamine metabolism in neural cells. Tyrosine hydroxylase, the rate-limiting enzyme for dopamine synthesis, was also found in intracellular tissue cysts in brain tissue with antibodies specific for the parasite-encoded tyrosine hydroxylase. These observations provide a mechanism for parasite-induced behavioral changes. The observed effects on dopamine metabolism could also be relevant in interpreting reports of psychobehavioral changes in toxoplasmosis-infected humans.

  13. Diagnosis of toxoplasmosis and typing of Toxoplasma gondii.

    Science.gov (United States)

    Liu, Quan; Wang, Ze-Dong; Huang, Si-Yang; Zhu, Xing-Quan

    2015-05-28

    Toxoplasmosis, caused by the obligate intracellular protozoan Toxoplasma gondii, is an important zoonosis with medical and veterinary importance worldwide. The disease is mainly contracted by ingesting undercooked or raw meat containing viable tissue cysts, or by ingesting food or water contaminated with oocysts. The diagnosis and genetic characterization of T. gondii infection is crucial for the surveillance, prevention and control of toxoplasmosis. Traditional approaches for the diagnosis of toxoplasmosis include etiological, immunological and imaging techniques. Diagnosis of toxoplasmosis has been improved by the emergence of molecular technologies to amplify parasite nucleic acids. Among these, polymerase chain reaction (PCR)-based molecular techniques have been useful for the genetic characterization of T. gondii. Serotyping methods based on polymorphic polypeptides have the potential to become the choice for typing T. gondii in humans and animals. In this review, we summarize conventional non-DNA-based diagnostic methods, and the DNA-based molecular techniques for the diagnosis and genetic characterization of T. gondii. These techniques have provided foundations for further development of more effective and accurate detection of T. gondii infection. These advances will contribute to an improved understanding of the epidemiology, prevention and control of toxoplasmosis.

  14. AN EVALUATION STUDY OF ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA) USING RECOMBINANT PROTEIN GRA1 FOR DETECTION OF IgG ANTIBODIES AGAINTS TOXOPLASMA GONDII INFECTIONS

    OpenAIRE

    Muflikhah, Nina Difla; Artama, Wayan Tunas

    2017-01-01

    Toxoplasmosis is an infectious disease caused by Toxoplasma gondii, an intracellular protozoan parasite that live inside the cells of the reticulo endothelial and parenchymal cells of human and animals (mammals and birds). Some cases of toxoplasmosis usually have no symptoms, but in any cases caused severe symptoms, such as hydrocephalus, microcephalus, intracranial calcification, retinal damage, brain abscess, mental retardation, lymphadenopathy, and others. Its severe symptoms usually showe...

  15. Infections by pathogens with different transmission modes in feral cats from urban and rural areas of Korea.

    Science.gov (United States)

    Hwang, Jusun; Gottdenker, Nicole; Oh, Dae-Hyun; Lee, Hang; Chun, Myung-Sun

    2017-12-31

    In this study, we examine prevalences of three infectious pathogens with different transmission modes ( Bartonella henselae , hemoplasma, and Toxoplasma gondii ) in feral cats from urban and rural habitats. Infection status of the three pathogens in blood samples (n = 117) was determined through molecular or serological diagnostic methods. Overall prevalence of hemoplasma, Toxoplasma gondii , and Bartonella henselae was 47.9%, 50%, and 35.7%, respectively. Comparing the two habitats, only seroprevalence of Bartonella henselae was significantly higher in urban cats. Based on the results, we discuss how pathogens with distinct transmission modes may show different prevalence between urban and rural habitat types.

  16. Manipulation of Host Cholesterol by Obligate Intracellular Bacteria

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    Dhritiman Samanta

    2017-05-01

    Full Text Available Cholesterol is a multifunctional lipid that plays important metabolic and structural roles in the eukaryotic cell. Despite having diverse lifestyles, the obligate intracellular bacterial pathogens Chlamydia, Coxiella, Anaplasma, Ehrlichia, and Rickettsia all target cholesterol during host cell colonization as a potential source of membrane, as well as a means to manipulate host cell signaling and trafficking. To promote host cell entry, these pathogens utilize cholesterol-rich microdomains known as lipid rafts, which serve as organizational and functional platforms for host signaling pathways involved in phagocytosis. Once a pathogen gains entrance to the intracellular space, it can manipulate host cholesterol trafficking pathways to access nutrient-rich vesicles or acquire membrane components for the bacteria or bacteria-containing vacuole. To acquire cholesterol, these pathogens specifically target host cholesterol metabolism, uptake, efflux, and storage. In this review, we examine the strategies obligate intracellular bacterial pathogens employ to manipulate cholesterol during host cell colonization. Understanding how obligate intracellular pathogens target and use host cholesterol provides critical insight into the host-pathogen relationship.

  17. Translational Control in Plasmodium and Toxoplasma Parasites

    Science.gov (United States)

    Joyce, Bradley R.; Sullivan, William J.; Nussenzweig, Victor

    2013-01-01

    The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis. PMID:23243065

  18. Translational control in Plasmodium and toxoplasma parasites.

    Science.gov (United States)

    Zhang, Min; Joyce, Bradley R; Sullivan, William J; Nussenzweig, Victor

    2013-02-01

    The life cycles of apicomplexan parasites such as Plasmodium spp. and Toxoplasma gondii are complex, consisting of proliferative and latent stages within multiple hosts. Dramatic transformations take place during the cycles, and they demand precise control of gene expression at all levels, including translation. This review focuses on the mechanisms that regulate translational control in Plasmodium and Toxoplasma, with a particular emphasis on the phosphorylation of the α subunit of eukaryotic translation initiation factor 2 (eIF2α). Phosphorylation of eIF2α (eIF2α∼P) is a conserved mechanism that eukaryotic cells use to repress global protein synthesis while enhancing gene-specific translation of a subset of mRNAs. Elevated levels of eIF2α∼P have been observed during latent stages in both Toxoplasma and Plasmodium, indicating that translational control plays a role in maintaining dormancy. Parasite-specific eIF2α kinases and phosphatases are also required for proper developmental transitions and adaptation to cellular stresses encountered during the life cycle. Identification of small-molecule inhibitors of apicomplexan eIF2α kinases may selectively interfere with parasite translational control and lead to the development of new therapies to treat malaria and toxoplasmosis.

  19. Toxoplasma gondii, source to sea: higher contribution of domestic felids to terrestrial parasite loading despite lower infection prevalence.

    Science.gov (United States)

    Vanwormer, Elizabeth; Conrad, Patricia A; Miller, Melissa A; Melli, Ann C; Carpenter, Tim E; Mazet, Jonna A K

    2013-09-01

    Environmental transmission of Toxoplasma gondii, a global zoonotic parasite, adversely impacts human and animal health. Toxoplasma is a significant cause of mortality in threatened Southern sea otters, which serve as sentinels for disease threats to people and animals in coastal environments. As wild and domestic felids are the only recognized hosts capable of shedding Toxoplasma oocysts into the environment, otter infection suggests land-to-sea pathogen transmission. To assess relative contributions to terrestrial parasite loading, we evaluated infection and shedding among managed and unmanaged feral domestic cats, mountain lions, and bobcats in coastal California, USA. Infection prevalence differed among sympatric felids, with a significantly lower prevalence for managed feral cats (17%) than mountain lions, bobcats, or unmanaged feral cats subsisting on wild prey (73-81%). A geographic hotspot of infection in felids was identified near Monterey Bay, bordering a high-risk site for otter infection. Increased odds of oocyst shedding were detected in bobcats and unmanaged feral cats. Due to their large populations, pet and feral domestic cats likely contribute more oocysts to lands bordering the sea otter range than native wild felids. Continued coastal development may influence felid numbers and distribution, increase terrestrial pathogens in freshwater runoff, and alter disease dynamics at the human-animal-environment interface.

  20. Seroprevalence of Toxoplasma gondii infection in slaughtered pigs ...

    African Journals Online (AJOL)

    Toxoplasmosis is a parasitic disease/infection of medical and veterinary importance. The causative agent; Toxoplasma gondii, can infect warm blooded animals, birds as well as humans. This study was designed to determine the seroprevalence of Toxoplasma gondii infection in slaughtered pigs in Makurdi, Nigeria.

  1. Cloning and expression of Toxoplasma gondii tachyzoite P22 protein

    African Journals Online (AJOL)

    Delay in diagnosis of Toxoplasma gondii infection in pregnant women who have been infected during the first trimester of gestation can lead to death of her fetus. Serological tests based on recombinant proteins are the main diagnosis methods for the detection of anti Toxoplasma antibody in serum samples. The aim of this ...

  2. Seroprevalence of Toxoplasma gondii and potential risk factors in ...

    African Journals Online (AJOL)

    Toxoplasma gondii infection is important in pigs and humans may get infected through the consumption of undercooked infected pork. This study conducted in Oyo state, Nigeria for 15 months (between February, 2012 and April, 2013) investigated the seroprevalence of Toxoplasma gondii infection in pigs reared on farms ...

  3. Seroprevalence of Toxoplasma gondii and Neospora caninum in ...

    African Journals Online (AJOL)

    Background: Toxoplasma gondii and Neospora caninum are protozoans infecting a wide range of mammals; the etiologic agents of Toxoplasmosis and Neosporosis respectively, This study investigated the prevalence of antibodies to Toxoplasma gondii and Neospora caninum in dogs from southwestern Nigeria. Materials ...

  4. Acidification of the parasitophorous vacuole containing Toxoplasma gondii in the presence of hydroxyurea

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    Cristiane S. Carvalho

    2006-09-01

    Full Text Available Toxoplasma gondii multiplies within parasitophorous vacuole that is not recognized by the primary no oxidative defense of host cells, mainly represented by the fusion with acidic organelles. Recent studies have already shown that hydroxyurea arrested the intracellular parasites leading to its destruction. In the present work we investigated the cellular mechanism involved in the destruction of intracellular Toxoplasma gondii. Fluorescent vital stains were used in order to observe possible acidification of parasitophorous vacuole-containing Toxoplasma gondii in presence of hydroxyurea. Vero cells infected with tachyzoites were treated with hydroxyurea for 12, 24 or 48 hours. Fluorescence, indicative of acidification, was observed in the parasitophorous vacuole when the cultures were incubated in presence of acridine orange. LysoTracker red was used in order to determine whether lysosomes were involved in the acidification process. An intense fluorescence was observed after 12 and 24 hours of incubation with hydroxyurea, achieving it is highly intensity after 48 hours of treatment. Ultrastructural cytochemistry for localization of the acid phosphatase lysosomal enzyme was realized. Treated infected cultures showed reaction product in vesicles fusing with vacuole or associated with intravacuolar parasites. These results suggest that fusion with lysosomes and acidification of parasitophorous vacuole leads to parasites destruction in the presence pf hydroxyurea.Toxoplasma gondii se multiplica dentro do vacúolo parasitóforo que não é reconhecido pela defesa primária não oxidativa de células hospedeiras: a fusão com organelas ácidas. Estudos anteriores mostraram que hidroxiuréia interrompeu a multiplicação dos parasitos intracelulares causando sua eliminação. No presente trabalho nós investigamos o mecanismo celular envolvido na destruição do Toxoplasma gondii intracelular. Marcadores vitais fluorescentes foram usados para observar a

  5. Global Analysis of Palmitoylated Proteins in Toxoplasma gondii.

    Science.gov (United States)

    Foe, Ian T; Child, Matthew A; Majmudar, Jaimeen D; Krishnamurthy, Shruthi; van der Linden, Wouter A; Ward, Gary E; Martin, Brent R; Bogyo, Matthew

    2015-10-14

    Post-translational modifications (PTMs) such as palmitoylation are critical for the lytic cycle of the protozoan parasite Toxoplasma gondii. While palmitoylation is involved in invasion, motility, and cell morphology, the proteins that utilize this PTM remain largely unknown. Using a chemical proteomic approach, we report a comprehensive analysis of palmitoylated proteins in T. gondii, identifying a total of 282 proteins, including cytosolic, membrane-associated, and transmembrane proteins. From this large set of palmitoylated targets, we validate palmitoylation of proteins involved in motility (myosin light chain 1, myosin A), cell morphology (PhIL1), and host cell invasion (apical membrane antigen 1, AMA1). Further studies reveal that blocking AMA1 palmitoylation enhances the release of AMA1 and other invasion-related proteins from apical secretory organelles, suggesting a previously unrecognized role for AMA1. These findings suggest that palmitoylation is ubiquitous throughout the T. gondii proteome and reveal insights into the biology of this important human pathogen. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. UNC93B1 mediates host resistance to infection with Toxoplasma gondii.

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    Mariane B Melo

    2010-08-01

    Full Text Available UNC93B1 associates with Toll-Like Receptor (TLR 3, TLR7 and TLR9, mediating their translocation from the endoplasmic reticulum to the endolysosome, hence allowing proper activation by nucleic acid ligands. We found that the triple deficient '3d' mice, which lack functional UNC93B1, are hyper-susceptible to infection with Toxoplasma gondii. We established that while mounting a normal systemic pro-inflammatory response, i.e. producing abundant MCP-1, IL-6, TNFα and IFNγ, the 3d mice were unable to control parasite replication. Nevertheless, infection of reciprocal bone marrow chimeras between wild-type and 3d mice with T. gondii demonstrated a primary role of hemopoietic cell lineages in the enhanced susceptibility of UNC93B1 mutant mice. The protective role mediated by UNC93B1 to T. gondii infection was associated with impaired IL-12 responses and delayed IFNγ by spleen cells. Notably, in macrophages infected with T. gondii, UNC93B1 accumulates on the parasitophorous vacuole. Furthermore, upon in vitro infection the rate of tachyzoite replication was enhanced in non-activated macrophages carrying mutant UNC93B1 as compared to wild type gene. Strikingly, the role of UNC93B1 on intracellular parasite growth appears to be independent of TLR function. Altogether, our results reveal a critical role for UNC93B1 on induction of IL-12/IFNγ production as well as autonomous control of Toxoplasma replication by macrophages.

  7. Genotyping of polymorphic effectors of Toxoplasma gondii isolates from China

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    Weisheng Cheng

    2017-11-01

    Full Text Available Abstract Background Toxoplasma gondii is an opportunistic protozoan apicomplexan and obligate intracellular parasite that infects a wide range of animals and humans. Rhoptry proteins 5 (ROP5, ROP16, ROP18 and dense granules 15 (GRA15 are the important effectors secreted by T. gondii which link to the strain virulence for mice and modulate the host’s response to the parasite. Little has been known about these molecules as well as GRA3 in type Chinese 1 strains that show polymorphism among strains of archetypical genotypes. This study examined the genetic diversity of these effectors and its correlated virulence in mice among T. gondii isolates from China. Results Twenty-one isolates from stray cats were detected, of which 15 belong to Chinese 1, and 6 to ToxoDB #205. Wh6 isolate, a Chinese 1 strain, has an avirulent phenotype. PCR-RFLP results of ROP5 and ROP18 presented few variations among the strains. Genotyping of GRA15 and ROP16 revealed that all the strains belong to type II allele except Xz7 which carries type I allele. ROP16 amino acid alignment at 503 locus demonstrated that 17 isolates are featured as type I or type III (ROP16I/III, and the other 4 as type II (ROP16II. The strains investigated may be divided into four groups based on GRA3 amino acid alignment, and all isolates of type Chinese 1 belong to the μ-1 allele except Wh6 which is identical to type II strain. Conclusions PCR-RFLP and sequence alignment analyses of ROP5, ROP16, ROP18, GRA3, and GRA15 in T. gondii revealed that strains with the same genotype may have variations in some of their key genes. GRA3 variation exhibited by Wh6 strain may be associated with the difference in phenotype and pathogenesis.

  8. Toxoplasma gondii sequesters lysosomes from mammalian hosts in the vacuolar space.

    Science.gov (United States)

    Coppens, Isabelle; Dunn, Joe Dan; Romano, Julia D; Pypaert, Marc; Zhang, Hui; Boothroyd, John C; Joiner, Keith A

    2006-04-21

    The intracellular compartment harboring Toxoplasma gondii satisfies the parasite's nutritional needs for rapid growth in mammalian cells. We demonstrate that the parasitophorous vacuole (PV) of T. gondii accumulates material coming from the host mammalian cell via the exploitation of the host endo-lysosomal system. The parasite actively recruits host microtubules, resulting in selective attraction of endo-lysosomes to the PV. Microtubule-based invaginations of the PV membrane serve as conduits for the delivery of host endo-lysosomes within the PV. These tubular conduits are decorated by a parasite coat, including the tubulogenic protein GRA7, which acts like a garrote that sequesters host endocytic organelles in the vacuolar space. These data define an unanticipated process allowing the parasite intimate and concentrated access to a diverse range of low molecular weight components produced by the endo-lysosomal system. More generally, they identify a unique mechanism for unidirectional transport and sequestration of host organelles.

  9. First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana from Yucatan, Mexico

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    M. Torres-Castro

    2016-03-01

    Full Text Available Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13 in brains. Positive amplicons were sequenced for analysis, this produced results similar to T. gondii with identity and coverage values of 98% and 96-100%, respectively. This study presents the first molecular evidence of the circulation of T. gondii in D. virginiana from Mexico.

  10. First molecular evidence of Toxoplasma gondii in opossums (Didelphis virginiana) from Yucatan, Mexico.

    Science.gov (United States)

    Torres-Castro, M; Noh-Pech, H; Puerto-Hernández, R; Reyes-Hernández, B; Panti-May, A; Hernández-Betancourt, S; Yeh-Gorocica, A; González-Herrera, L; Zavala-Castro, J; Puerto, F I

    2016-01-01

    Toxoplasma gondii is an obligate intracellular parasite recognized as a causal agent of toxoplasmosis; zoonotic disease endemic in many countries worldwide, including Mexico. Different species of animals participate in the wild cycle infection, including opossums of the species Didelphis virginiana. Thirteen D. virginiana were captured in Yucatan, Mexico. Detection of T. gondii was achieved by Polymerase Chain Reaction, which determined an infection of 76.9% (10/13) in brains. Positive amplicons were sequenced for analysis, this produced results similar to T. gondii with identity and coverage values of 98% and 96-100%, respectively. This study presents the first molecular evidence of the circulation of T. gondii in D. virginiana from Mexico.

  11. Beneficial Effects of Capparis Spinosa Honey on the Immune Response of Rats Infected with Toxoplasma Gundii

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    Ahmed Gaffer Hegazi

    2017-06-01

    Full Text Available Objectives: The Toxoplasma gondii (T. gondii is an intracellular opportunistic protozoan parasite that infects approximately one-third of the human population worldwide. Honey has long been used for treatment of many diseases in folk medicine. Honey has exhibited significant anthelmintic, nematicidal and anti-protozoal activities. This study was conducted to investigate the immunological patterns in rats infected with T. gondii who were treated orally with supplemented 15% Capparis spinosa honey (Saudi Arabia for a period of 28 days. Methods: Immunoglobulin M, immunoglobulin G, and cytokines were detected by using enzyme-linked immunosorbent assays (ELISAs. In addition, the mortality and the morbidity rates were assessed. Results: Oral administration of Capparis spinosa honey as a natural food additive was experimentally shown to increase the antibody titer; furthermore, compared with the rats in the control group,

  12. Detection of Toxoplasma gondii in a free-ranging giant anteater

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    Thais Oliveira Morgado

    Full Text Available ABSTRACT: Toxoplasmosis is caused by Toxoplasma gondii, an obligatory intracellular protozoan, which establishes acute and chronic infections in birds and mammals, including humans. This note reports, for the first time, the detection and sequencing of DNA from T. gondii in the peripheral blood of a young free range giant anteater (Myrmecophaga tridactyla. For the diagnosis, the following methods were used: polymerase chain reaction (PCR and positive serology (1:800 by means of the modified agglutination test (MAT. Since this species may be consumed by humans and predated by wild felids, its importance is emphasized as a probable source of zoonotic infection, in addition to its possible participation in the infection enzootic cycle. Although, parasitemia has been confirmed in this specimen, it presented no clinical sign of infection.

  13. Ortholog-based screening and identification of genes related to intracellular survival.

    Science.gov (United States)

    Yang, Xiaowen; Wang, Jiawei; Bing, Guoxia; Bie, Pengfei; De, Yanyan; Lyu, Yanli; Wu, Qingmin

    2018-04-20

    Bioinformatics and comparative genomics analysis methods were used to predict unknown pathogen genes based on homology with identified or functionally clustered genes. In this study, the genes of common pathogens were analyzed to screen and identify genes associated with intracellular survival through sequence similarity, phylogenetic tree analysis and the λ-Red recombination system test method. The total 38,952 protein-coding genes of common pathogens were divided into 19,775 clusters. As demonstrated through a COG analysis, information storage and processing genes might play an important role intracellular survival. Only 19 clusters were present in facultative intracellular pathogens, and not all were present in extracellular pathogens. Construction of a phylogenetic tree selected 18 of these 19 clusters. Comparisons with the DEG database and previous research revealed that seven other clusters are considered essential gene clusters and that seven other clusters are associated with intracellular survival. Moreover, this study confirmed that clusters screened by orthologs with similar function could be replaced with an approved uvrY gene and its orthologs, and the results revealed that the usg gene is associated with intracellular survival. The study improves the current understanding of intracellular pathogens characteristics and allows further exploration of the intracellular survival-related gene modules in these pathogens. Copyright © 2018. Published by Elsevier B.V.

  14. Subversion of the cytoskeleton by intracellular bacteria: lessons from Listeria, Salmonella, and Vibrio

    Science.gov (United States)

    de Souza Santos, Marcela; Orth, Kim

    2018-01-01

    Summary Entry into host cells and intracellular persistence by invasive bacteria are tightly coupled to the ability of the bacterium to disrupt the eukaryotic cytoskeletal machinery. Herein we review the main strategies used by three intracellular pathogens to harness key modulators of the cytoskeleton. Two of these bacteria, namely Listeria monocytogenes and Salmonella enterica serovar Typhimurium, exhibit quite distinct intracellular lifestyles, and therefore, provide a comprehensive panel for the understanding of the intricate bacteria-cytoskeleton interplay during infections. The emerging intracellular pathogen Vibrio parahaemolyticus is depicted as a developing model for the uncovering of novel mechanisms used to hijack the cytoskeleton. PMID:25440316

  15. Evidence for a structural role for acid-fast lipids in oocyst walls of Cryptosporidium, Toxoplasma, and Eimeria.

    Science.gov (United States)

    Bushkin, G Guy; Motari, Edwin; Carpentieri, Andrea; Dubey, Jitender P; Costello, Catherine E; Robbins, Phillips W; Samuelson, John

    2013-09-03

    Coccidia are protozoan parasites that cause significant human disease and are of major agricultural importance. Cryptosporidium spp. cause diarrhea in humans and animals, while Toxoplasma causes disseminated infections in fetuses and untreated AIDS patients. Eimeria is a major pathogen of commercial chickens. Oocysts, which are the infectious form of Cryptosporidium and Eimeria and one of two infectious forms of Toxoplasma (the other is tissue cysts in undercooked meat), have a multilayered wall. Recently we showed that the inner layer of the oocyst walls of Toxoplasma and Eimeria is a porous scaffold of fibers of β-1,3-glucan, which are also present in fungal walls but are absent from Cryptosporidium oocyst walls. Here we present evidence for a structural role for lipids in the oocyst walls of Cryptosporidium, Toxoplasma, and Eimeria. Briefly, oocyst walls of each organism label with acid-fast stains that bind to lipids in the walls of mycobacteria. Polyketide synthases similar to those that make mycobacterial wall lipids are abundant in oocysts of Toxoplasma and Eimeria and are predicted in Cryptosporidium. The outer layer of oocyst wall of Eimeria and the entire oocyst wall of Cryptosporidium are dissolved by organic solvents. Oocyst wall lipids are complex mixtures of triglycerides, some of which contain polyhydroxy fatty acyl chains like those present in plant cutin or elongated fatty acyl chains like mycolic acids. We propose a two-layered model of the oocyst wall (glucan and acid-fast lipids) that resembles the two-layered walls of mycobacteria (peptidoglycan and acid-fast lipids) and plants (cellulose and cutin). Oocysts, which are essential for the fecal-oral spread of coccidia, have a wall that is thought responsible for their survival in the environment and for their transit through the stomach and small intestine. While oocyst walls of Toxoplasma and Eimeria are strengthened by a porous scaffold of fibrils of β-1,3-glucan and by proteins cross

  16. The effects of demographic, social, and environmental characteristics on pathogen prevalence in wild felids across a gradient of urbanization.

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    Jesse S Lewis

    Full Text Available Transmission of pathogens among animals is influenced by demographic, social, and environmental factors. Anthropogenic alteration of landscapes can impact patterns of disease dynamics in wildlife populations, increasing the potential for spillover and spread of emerging infectious diseases in wildlife, human, and domestic animal populations. We evaluated the effects of multiple ecological mechanisms on patterns of pathogen exposure in animal populations. Specifically, we evaluated how ecological factors affected the prevalence of Toxoplasma gondii (Toxoplasma, Bartonella spp. (Bartonella, feline immunodeficiency virus (FIV, and feline calicivirus (FCV in bobcat and puma populations across wildland-urban interface (WUI, low-density exurban development, and wildland habitat on the Western Slope (WS and Front Range (FR of Colorado during 2009-2011. Samples were collected from 37 bobcats and 29 pumas on the WS and FR. As predicted, age appeared to be positively related to the exposure to pathogens that are both environmentally transmitted (Toxoplasma and directly transmitted between animals (FIV. In addition, WS bobcats appeared more likely to be exposed to Toxoplasma with increasing intraspecific space-use overlap. However, counter to our predictions, exposure to directly-transmitted pathogens (FCV and FIV was more likely with decreasing space-use overlap (FCV: WS bobcats and potential intraspecific contacts (FIV: FR pumas. Environmental factors, including urbanization and landscape covariates, were generally unsupported in our models. This study is an approximation of how pathogens can be evaluated in relation to demographic, social, and environmental factors to understand pathogen exposure in wild animal populations.

  17. An Extended Surface Loop on Toxoplasma gondii Apical Membrane Antigen 1 (AMA1 Governs Ligand Binding Selectivity.

    Directory of Open Access Journals (Sweden)

    Michelle L Parker

    Full Text Available Apicomplexan parasites are the causative agents of globally prevalent diseases including malaria and toxoplasmosis. These obligate intracellular pathogens have evolved a sophisticated host cell invasion strategy that relies on a parasite-host cell junction anchored by interactions between apical membrane antigens (AMAs on the parasite surface and rhoptry neck 2 (RON2 proteins discharged from the parasite and embedded in the host cell membrane. Key to formation of the AMA1-RON2 complex is displacement of an extended surface loop on AMA1 called the DII loop. While conformational flexibility of the DII loop is required to expose the mature RON2 binding groove, a definitive role of this substructure has not been elucidated. To establish a role of the DII loop in Toxoplasma gondii AMA1, we engineered a form of the protein where the mobile portion of the loop was replaced with a short Gly-Ser linker (TgAMA1ΔDIIloop. Isothermal titration calorimetry measurements with a panel of RON2 peptides revealed an influential role for the DII loop in governing selectivity. Most notably, an Eimeria tenella RON2 (EtRON2 peptide that showed only weak binding to TgAMA1 bound with high affinity to TgAMA1ΔDIIloop. To define the molecular basis for the differential binding, we determined the crystal structure of TgAMA1ΔDIIloop in complex with the EtRON2 peptide. When analyzed in the context of existing AMA1-RON2 structures, spatially distinct anchor points in the AMA1 groove were identified that, when engaged, appear to provide the necessary traction to outcompete the DII loop. Collectively, these data support a model where the AMA1 DII loop serves as a structural gatekeeper to selectively filter out ligands otherwise capable of binding with high affinity in the AMA1 apical groove. These data also highlight the importance of considering the functional implications of the DII loop in the ongoing development of therapeutic intervention strategies targeting the AMA1-RON

  18. A plant/fungal-type phosphoenolpyruvate carboxykinase located in the parasite mitochondrion ensures glucose-independent survival of Toxoplasma gondii.

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    Nitzsche, Richard; Günay-Esiyok, Özlem; Tischer, Maximilian; Zagoriy, Vyacheslav; Gupta, Nishith

    2017-09-15

    Toxoplasma gondii is considered to be one of the most successful intracellular pathogens, because it can reproduce in varied nutritional milieus, encountered in diverse host cell types of essentially any warm-blooded organism. Our earlier work demonstrated that the acute (tachyzoite) stage of T. gondii depends on cooperativity of glucose and glutamine catabolism to meet biosynthetic demands. Either of these two nutrients can sustain the parasite survival; however, what determines the metabolic plasticity has not yet been resolved. Here, we reveal two discrete phosphoenolpyruvate carboxykinase (PEPCK) enzymes in the parasite, one of which resides in the m i t ochondrion ( Tg PEPCK mt ), whereas the other protein is n ot e xpressed in t achyzoites ( Tg PEPCK net ). Parasites with an intact glycolysis can tolerate genetic deletions of Tg PEPCK mt as well as of Tg PEPCK net , indicating their nonessential roles for tachyzoite survival. Tg PEPCK net can also be ablated in a glycolysis-deficient mutant, while Tg PEPCK mt is refractory to deletion. Consistent with this, the lytic cycle of a conditional mutant of Tg PEPCK mt in the glycolysis-impaired strain was aborted upon induced repression of the mitochondrial isoform, demonstrating its essential role for the glucose-independent survival of parasites. Isotope-resolved metabolomics of the conditional mutant revealed defective flux of glutamine-derived carbon into RNA-bound ribose sugar as well as metabolites associated with gluconeogenesis, entailing a critical nodal role of PEPCK mt in linking catabolism of glucose and glutamine with anabolic pathways. Our data also suggest a homeostatic function of Tg PEPCK mt in cohesive operation of glycolysis and the tricarboxylic acid cycle in a normal glucose-replete milieu. Conversely, we found that the otherwise integrative enzyme pyruvate carboxylase ( Tg PyC) is dispensable not only in glycolysis-competent but also in glycolysis-deficient tachyzoites despite a mitochondrial

  19. β-1,3-Glucan, Which Can Be Targeted by Drugs, Forms a Trabecular Scaffold in the Oocyst Walls of Toxoplasma and Eimeria

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    Bushkin, G. Guy; Motari, Edwin; Magnelli, Paula; Gubbels, Marc-Jan; Dubey, Jitender P.; Miska, Katarzyna B.; Bullitt, Esther; Costello, Catherine E.; Robbins, Phillips W.; Samuelson, John

    2012-01-01

    ABSTRACT The walls of infectious pathogens, which are essential for transmission, pathogenesis, and diagnosis, contain sugar polymers that are defining structural features, e.g., β-1,3-glucan and chitin in fungi, chitin in Entamoeba cysts, β-1,3-GalNAc in Giardia cysts, and peptidoglycans in bacteria. The goal here was to determine in which of three walled forms of Toxoplasma gondii (oocyst, sporocyst, or tissue cyst) is β-1,3-glucan, the product of glucan synthases and glucan hydrolases predicted by whole-genome sequences of the parasite. The three most important discoveries were as follows. (i) β-1,3-glucan is present in oocyst walls of Toxoplasma and Eimeria (a chicken parasite that is a model for intestinal stages of Toxoplasma) but is absent from sporocyst and tissue cyst walls. (ii) Fibrils of β-1,3-glucan are part of a trabecular scaffold in the inner layer of the oocyst wall, which also includes a glucan hydrolase that has a novel glucan-binding domain. (iii) Echinocandins, which target the glucan synthase and kill fungi, arrest development of the Eimeria oocyst wall and prevent release of the parasites into the intestinal lumen. In summary, β-1,3-glucan, which can be targeted by drugs, is an important component of oocyst walls of Toxoplasma but is not a component of sporocyst and tissue cyst walls. PMID:23015739

  20. Secretome of obligate intracellular Rickettsia

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    Gillespie, Joseph J.; Kaur, Simran J.; Rahman, M. Sayeedur; Rennoll-Bankert, Kristen; Sears, Khandra T.; Beier-Sexton, Magda; Azad, Abdu F.

    2014-01-01

    The genus Rickettsia (Alphaproteobacteria, Rickettsiales, Rickettsiaceae) is comprised of obligate intracellular parasites, with virulent species of interest both as causes of emerging infectious diseases and for their potential deployment as bioterrorism agents. Currently, there are no effective commercially available vaccines, with treatment limited primarily to tetracycline antibiotics, although others (e.g. josamycin, ciprofloxacin, chloramphenicol, and azithromycin) are also effective. Much of the recent research geared toward understanding mechanisms underlying rickettsial pathogenicity has centered on characterization of secreted proteins that directly engage eukaryotic cells. Herein, we review all aspects of the Rickettsia secretome, including six secretion systems, 19 characterized secretory proteins, and potential moonlighting proteins identified on surfaces of multiple Rickettsia species. Employing bioinformatics and phylogenomics, we present novel structural and functional insight on each secretion system. Unexpectedly, our investigation revealed that the majority of characterized secretory proteins have not been assigned to their cognate secretion pathways. Furthermore, for most secretion pathways, the requisite signal sequences mediating translocation are poorly understood. As a blueprint for all known routes of protein translocation into host cells, this resource will assist research aimed at uniting characterized secreted proteins with their apposite secretion pathways. Furthermore, our work will help in the identification of novel secreted proteins involved in rickettsial ‘life on the inside’. PMID:25168200

  1. Microsporidia are natural intracellular parasites of the nematode Caenorhabditis elegans.

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    Troemel, Emily R; Félix, Marie-Anne; Whiteman, Noah K; Barrière, Antoine; Ausubel, Frederick M

    2008-12-09

    For decades the soil nematode Caenorhabditis elegans has been an important model system for biology, but little is known about its natural ecology. Recently, C. elegans has become the focus of studies of innate immunity and several pathogens have been shown to cause lethal intestinal infections in C. elegans. However none of these pathogens has been shown to invade nematode intestinal cells, and no pathogen has been isolated from wild-caught C. elegans. Here we describe an intracellular pathogen isolated from wild-caught C. elegans that we show is a new species of microsporidia. Microsporidia comprise a large class of eukaryotic intracellular parasites that are medically and agriculturally important, but poorly understood. We show that microsporidian infection of the C. elegans intestine proceeds through distinct stages and is transmitted horizontally. Disruption of a conserved cytoskeletal structure in the intestine called the terminal web correlates with the release of microsporidian spores from infected cells, and appears to be part of a novel mechanism by which intracellular pathogens exit from infected cells. Unlike in bacterial intestinal infections, the p38 MAPK and insulin/insulin-like growth factor (IGF) signaling pathways do not appear to play substantial roles in resistance to microsporidian infection in C. elegans. We found microsporidia in multiple wild-caught isolates of Caenorhabditis nematodes from diverse geographic locations. These results indicate that microsporidia are common parasites of C. elegans in the wild. In addition, the interaction between C. elegans and its natural microsporidian parasites provides a system in which to dissect intracellular intestinal infection in vivo and insight into the diversity of pathogenic mechanisms used by intracellular microbes.

  2. Seroprevalence of Toxoplasma gondii and Neospora caninum in red deer from Central Italy

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    Guido Rocchigiani

    2016-09-01

    Full Text Available Neospora caninum and Toxoplasma gondii are cosmopolite protozoan parasites impacting on human and animal health. In particular, T. gondii commonly infects human beings and all warm-blooded animals, while N. caninum is responsible for bovine abortion and neuromuscular disease in dogs. The aim of the presented survey was to evaluate the occurrence and prevalence of these parasites in the most numerous Italian red deer population. The sera of 60 red deer ( Cervus elaphus inhabiting Central Italy (43°56’N 10°55’E and killed by selective hunting were examined using an indirect fluorescent antibody test (IFAT for both N. caninum and T. gondii antibodies. White blood cells (buffy coat were also checked by PCR and T. gondii DNA was genotyped. Thirteen out of 60 sera (22% scored positive for Toxoplasma, 17 samples (28% were Neospora positive. Coinfection was recorded in 5 cases (8%. T. gondii (genotype II and N. caninum DNA was detected in one and 3 samples of buffy coat, respectively. The presented study is the first to examine the occurrence of these parasites in the most numerous red deer Italian population, confirming this animal species as carrier of the investigated pathogens. These animals spread near human settlements, co-inhabiting with final hosts of [i]T. gondii[/i] and N. caninum and could contribute to their transmission to domestic ruminants and humans. In particular, the seroprevalence value for N. caninum was the highest among European records.

  3. Probable neuroimmunological link between Toxoplasma and cytomegalovirus infections and personality changes in the human host

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    Roubalová Kateřina

    2005-07-01

    Full Text Available Abstract Background Recently, a negative association between Toxoplasma-infection and novelty seeking was reported. The authors suggested that changes of personality trait were caused by manipulation activity of the parasite, aimed at increasing the probability of transmission of the parasite from an intermediate to a definitive host. They also suggested that low novelty seeking indicated an increased level of the neurotransmitter dopamine in the brain of infected subjects, a phenomenon already observed in experimentally infected rodents. However, the changes in personality can also be just a byproduct of any neurotropic infection. Moreover, the association between a personality trait and the toxoplasmosis can even be caused by an independent correlation of both the probability of Toxoplasma-infection and the personality trait with the third factor, namely with the size of living place of a subject. To test these two alternative hypotheses, we studied the influence of another neurotropic pathogen, the cytomegalovirus, on the personality of infected subjects, and reanalyzed the original data after the effect of the potential confounder, the size of living place, was controlled. Methods In the case-control study, 533 conscripts were tested for toxoplasmosis and presence of anti-cytomegalovirus antibodies and their novelty seeking was examined with Cloninger's TCI questionnaire. Possible association between the two infections and TCI dimensions was analyzed. Results The decrease of novelty seeking is associated also with cytomegalovirus infection. After the size of living place was controlled, the effect of toxoplasmosis on novelty seeking increased. Significant difference in novelty seeking was observed only in the largest city, Prague. Conclusion Toxoplasma and cytomegalovirus probably induce a decrease of novelty seeking. As the cytomegalovirus spreads in population by direct contact (not by predation as with Toxoplasma, the observed changes are

  4. Toxoplasma gondii infection in humans in China

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    He Shenyi

    2011-08-01

    Full Text Available Abstract Toxoplasmosis is a zoonotic infection of humans and animals, caused by the opportunistic protozoan Toxoplasma gondii, a parasite belonging to the phylum Apicomplexa. Infection in pregnant women may lead to abortion, stillbirth or other serious consequences in newborns. Infection in immunocompromised patients can be fatal if not treated. On average, one third of people are chronically infected worldwide. Although very limited information from China has been published in the English journals, T. gondii infection is actually a significant human health problem in China. In the present article, we reviewed the clinical features, transmission, prevalence of T. gondii infection in humans in China, and summarized genetic characterizations of reported T. gondii isolates. Educating the public about the risks associated with unhealthy food and life style habits, tracking serological examinations to special populations, and measures to strengthen food and occupational safety are discussed.

  5. Toxoplasma gondii, Mental Health and Shizophrenia

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    Sibel Cevizci

    2013-04-01

    Full Text Available Protecting and promoting of mental health is one of the major application areas of public health. In particular, Toxoplasma gondii, which is a protozoal zoonosis common in Turkey, it is closely related to veterinary public health. In recent years, T.gondii can induce behavioral changes, may play a role in schizophrenia as an etiologic factor. Results of the recently performed studies shows that T.gondii may be a potential factor for some neuropathological changes in brain and suicide attemption. The purpose of this review is to present the data on recent epidemiology of T.gondii, mental health effects (changes in behavior, suicide, etc., the relationship between T.gondii and schizophrenia and offer some recommendations for protecting of public health. [TAF Prev Med Bull 2013; 12(2.000: 199-208

  6. Crioconservación de toxoplasma gondii

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    Sofía Duque Beltrán

    1992-03-01

    Full Text Available Toxoplasma gondii fue crioconservado en nitrógeno líquido usando como preservativo glicerol al 10% con el fin de mantener el protozoo por un largo período de tiempo. El descongelamiento de T. gondii se llevó a cabo, cuando los parásitos fueron requeridos para uso como antígeno, a los 10, 40 y 270 días siguientes a su crioconservación. La viabilidad y patogenicidad del parásito fue confirmada in vivo. La crioconservación de T. gondii disminuyó los costos de mantenimiento in vivo y de recursos humanos tanto en el bioterio como en el laboratorio.

  7. Frequency of exposure of endangered Caspian seals to Canine distemper virus, Leptospira interrogans, and Toxoplasma gondii.

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    Somayeh Namroodi

    Full Text Available Canine distemper virus (CDV, Leptospira interrogans, and Toxoplasma gondii are potentially lethal pathogens associated with decline in marine mammal populations. The Caspian Sea is home for the endangered Caspian seal (Pusa caspica. In the late 1990s and early 2000s, CDV caused a series of mortality events involving at least several thousand Caspian seals. To assess current infection status in Caspian seals, we surveyed for antibodies to three pathogens with potential to cause mortality in marine mammals. During 2015-2017, we tested serum samples from 36, apparently healthy, Caspian seals, accidentally caught in fishing nets in the Caspian Sea off Northern Iran, for antibodies to CDV, L. interrogans, and T. gondii, by virus neutralization, microscopic agglutination, and modified agglutination, respectively. Twelve (33%, 6 (17%, and 30 (83% samples were positive for CDV, L. interrogans and T. gondii antibodies, respectively. The highest titers of CDV, L. interrogans, and T. gondii antibodies were 16, 400, and 50, respectively. Frequencies of antibody to these pathogens were higher in seals >1 year old compared to seals <1 year old. Two serovars of L. interrogans (Pomona and Canicola were detected. Our results suggest a need for additional studies to clarify the impact of these pathogens on Caspian seal population decline and the improvement of management programs, including systematic screening to detect and protect the remaining population from disease outbreaks.

  8. Frequency of exposure of endangered Caspian seals to Canine distemper virus, Leptospira interrogans, and Toxoplasma gondii.

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    Namroodi, Somayeh; Shirazi, Amir S; Khaleghi, Seyyed Reza; N Mills, James; Kheirabady, Vahid

    2018-01-01

    Canine distemper virus (CDV), Leptospira interrogans, and Toxoplasma gondii are potentially lethal pathogens associated with decline in marine mammal populations. The Caspian Sea is home for the endangered Caspian seal (Pusa caspica). In the late 1990s and early 2000s, CDV caused a series of mortality events involving at least several thousand Caspian seals. To assess current infection status in Caspian seals, we surveyed for antibodies to three pathogens with potential to cause mortality in marine mammals. During 2015-2017, we tested serum samples from 36, apparently healthy, Caspian seals, accidentally caught in fishing nets in the Caspian Sea off Northern Iran, for antibodies to CDV, L. interrogans, and T. gondii, by virus neutralization, microscopic agglutination, and modified agglutination, respectively. Twelve (33%), 6 (17%), and 30 (83%) samples were positive for CDV, L. interrogans and T. gondii antibodies, respectively. The highest titers of CDV, L. interrogans, and T. gondii antibodies were 16, 400, and 50, respectively. Frequencies of antibody to these pathogens were higher in seals >1 year old compared to seals <1 year old. Two serovars of L. interrogans (Pomona and Canicola) were detected. Our results suggest a need for additional studies to clarify the impact of these pathogens on Caspian seal population decline and the improvement of management programs, including systematic screening to detect and protect the remaining population from disease outbreaks.

  9. A protein extract and a cysteine protease inhibitor enriched fraction from Jatropha curcas seed cake have in vitro anti-Toxoplasma gondii activity.

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    Soares, A M S; Carvalho, L P; Melo, E J T; Costa, H P S; Vasconcelos, I M; Oliveira, J T A

    2015-06-01

    Toxoplasma gondii is a parasite of great medical and veterinary importance that has worldwide distribution and causes toxoplasmosis. There are few treatments available for toxoplasmosis and the search for plant extracts and compounds with anti-Toxoplasma activity is of utmost importance for the discovery of new active drugs. The objective of this study was to investigate the action of a protein extract and a protease inhibitor enriched fraction from J. curcas seed cake on developing tachyzoites of T. gondii-infected Vero cells. The protein extract (JcCE) was obtained after solubilization of the J. curcas seed cake with 100 mM sodium borate buffer, pH 10, centrifugation and dialysis of the resulting supernatant with the extracting buffer. JcCE was used for the in vitro assays of anti-Toxoplasma activity at 0.01, 0.1, 0.5, 1.5, 3.0 and 5.0 mg/ml concentration for 24 h. The results showed that JcCE reduced the percentage of infection and the number of intracellular parasites, but had no effect on the morphology of Vero cells up to 3.0 mg/mL. The cysteine protease inhibitor enriched fraction, which was obtained after chromatography of JcCE on Sephadex G-75 and presented a unique protein band following SDS-PAGE, reduced both the number of T. gondii infected cells and intracellular parasites. These results suggest that both JcCE and the cysteine protease inhibitor enriched fraction interfere with the intracellular growth of T. gondii. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Intracellular Bacterial Infections: A Challenge for Developing Cellular Mediated Immunity Vaccines for Farmed Fish

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    Hetron Mweemba Munang’andu

    2018-04-01

    Full Text Available Aquaculture is one of the most rapidly expanding farming systems in the world. Its rapid expansion has brought with it several pathogens infecting different fish species. As a result, there has been a corresponding expansion in vaccine development to cope with the increasing number of infectious diseases in aquaculture. The success of vaccine development for bacterial diseases in aquaculture is largely attributed to empirical vaccine designs based on inactivation of whole cell (WCI bacteria vaccines. However, an upcoming challenge in vaccine design is the increase of intracellular bacterial pathogens that are not responsive to WCI vaccines. Intracellular bacterial vaccines evoke cellular mediated immune (CMI responses that “kill” and eliminate infected cells, unlike WCI vaccines that induce humoral immune responses whose protective mechanism is neutralization of extracellular replicating pathogens by antibodies. In this synopsis, I provide an overview of the intracellular bacterial pathogens infecting different fish species in aquaculture, outlining their mechanisms of invasion, replication, and survival intracellularly based on existing data. I also bring into perspective the current state of CMI understanding in fish together with its potential application in vaccine development. Further, I highlight the immunological pitfalls that have derailed our ability to produce protective vaccines against intracellular pathogens for finfish. Overall, the synopsis put forth herein advocates for a shift in vaccine design to include CMI-based vaccines against intracellular pathogens currently adversely affecting the aquaculture industry.

  11. A seroepidemiological survey of Toxoplasma gondii infection in referred dogs to Veterinary Hospital of Ahvaz, Iran

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    Fatemeh Zarra-Nezhad

    2017-12-01

    Full Text Available Toxoplasma gondii is an intracellular protozoan parasite, which is the cause of toxoplasmosis and can infect a wide variety of warm-blooded animals, including dogs and humans. The present study evaluated the seroprevalence of T. gondii infection in pet dogs in Ahvaz, southwest city of Iran, and investigated the related possible risk factors. A total of 180 serum samples were collected from dogs referred to Veterinary Hospital of Ahvaz. The samples were then tested by indirect enzyme-linked immunosorbent assay. The prevalence of T. gondii antibodies were 46.67%. Logistic regression and chi square tests were used for evaluating of risk factors. The positivity increased statistically significantly with dog’s gender (56% females and 39% males, P = 0.001, age (18% in <2 years old, 96% in ≥4 years old, P = 0.001 and place of living (47% outdoor dogs 38% house hold dogs, P = 0.025. However, no statistically significant association was found with dogs’ breed, deworming, food ingestion or contact with cats. Overall, the results showed a relatively high seroprevalence of T. gondii infection in dogs in southwest Iran (Ahvaz and proved association of T. gondii prevalence rates with the dog’s age, gender and place of living. Keywords: Toxoplasma gondii, Toxoplasmosis, Indirect enzyme-linked immunosorbent assay, Outdoor dogs, House hold dogs, Deworming

  12. DNA Amplification Techniques for the Detection of Toxoplasma gondii Tissue Cysts in Meat Producing Animals: A Narrative Review Article

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    Farooq RIAZ

    2016-12-01

    Full Text Available Background: Toxoplasma gondii is an intracellular parasite, which infects one-third population of world. Humans and animals acquire infection by ingesting oocytes from feces of cats or by meat of other animals having cysts that may lead to congenital, ocular or cephalic toxoplasmosis. Either it is important to detect T. gondii from meat of food animals from retail shops or directly at slaughterhouses, which is meant for export.Methods: The current research was done without time limitation using such terms as follows: “Toxoplasma gondii”, “Meat”, “Tissue cyst”, “PCR”, “LAMP”, “Screening” and “Immunological assay” alone or in combination, in English language. The used electronic databases for searching included as follows: PubMed, Scopus, Google Scholar, Web of Science and Science Direct. The searches were limited to the published papers to English language.Results: Sensitivity of different molecular techniques for diagnosis of Toxoplasma is real-time PCR > LAMP > conventional PCR. In addition to these DNA analysis tools, bioassay in mice and cats is considered as “gold standard” to detect T. gondii. Conclusion: This review article will help the readers for grasping advantages and limitations of different diagnostic tools for screening meat samples for T. gondii. This review also makes bibliography about the type of meat sample to be processed for diagnosis and different primers or sequences to be targeted for T. gondii by number of researches for its detection from meat or tissue sample using DNA amplification techniques.

  13. MYR1-Dependent Effectors Are the Major Drivers of a Host Cell’s Early Response to Toxoplasma, Including Counteracting MYR1-Independent Effects

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    Adit Naor

    2018-04-01

    Full Text Available The obligate intracellular parasite Toxoplasma gondii controls its host cell from within the parasitophorous vacuole (PV by using a number of diverse effector proteins, a subset of which require the aspartyl protease 5 enzyme (ASP5 and/or the recently discovered MYR1 protein to cross the PV membrane. To examine the impact these effectors have in the context of the entirety of the host response to Toxoplasma, we used RNA-Seq to analyze the transcriptome expression profiles of human foreskin fibroblasts infected with wild-type RH (RH-WT, RHΔmyr1, and RHΔasp5 tachyzoites. Interestingly, the majority of the differentially regulated genes responding to Toxoplasma infection are MYR1 dependent. A subset of MYR1 responses were ASP5 independent, and MYR1 function did not require ASP5 cleavage, suggesting the export of some effectors requires only MYR1. Gene set enrichment analysis of MYR1-dependent host responses suggests an upregulation of E2F transcription factors and the cell cycle and a downregulation related to interferon signaling, among numerous others. Most surprisingly, “hidden” responses arising in RHΔmyr1- but not RH-WT-infected host cells indicate counterbalancing actions of MYR1-dependent and -independent activities. The host genes and gene sets revealed here to be MYR1 dependent provide new insight into the parasite’s ability to co-opt host cell functions.

  14. Exploring anti-bacterial compounds against intracellular Legionella.

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    Christopher F Harrison

    Full Text Available Legionella pneumophila is a ubiquitous fresh-water bacterium which reproduces within its erstwhile predators, environmental amoeba, by subverting the normal pathway of phagocytosis and degradation. The molecular mechanisms which confer resistance to amoeba are apparently conserved and also allow replication within macrophages. Thus, L. pneumophila can act as an 'accidental' human pathogen and cause a severe pneumonia known as Legionnaires' disease. The intracellular localisation of L. pneumophila protects it from some antibiotics, and this fact must be taken into account to develop new anti-bacterial compounds. In addition, the intracellular lifestyle of L. pneumophila may render the bacteria susceptible to compounds diminishing bacterial virulence and decreasing intracellular survival and replication of this pathogen. The development of a single infection cycle intracellular replication assay using GFP-producing L. pneumophila and Acanthamoebacastellanii amoeba is reported here. This fluorescence-based assay allows for continuous monitoring of intracellular replication rates, revealing the effect of bacterial gene deletions or drug treatment. To examine how perturbations of the host cell affect L. pneumophila replication, several known host-targeting compounds were tested, including modulators of cytoskeletal dynamics, vesicle scission and Ras GTPase localisation. Our results reveal a hitherto unrealized potential antibiotic property of the β-lactone-based Ras depalmitoylation inhibitor palmostatin M, but not the closely related inhibitor palmostatin B. Further characterisation indicated that this compound caused specific growth inhibition of Legionella and Mycobacterium species, suggesting that it may act on a common bacterial target.

  15. Exploring Anti-Bacterial Compounds against Intracellular Legionella

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    Harrison, Christopher F.; Kicka, Sébastien; Trofimov, Valentin; Berschl, Kathrin; Ouertatani-Sakouhi, Hajer; Ackermann, Nikolaus; Hedberg, Christian; Cosson, Pierre; Soldati, Thierry; Hilbi, Hubert

    2013-01-01

    Legionella pneumophila is a ubiquitous fresh-water bacterium which reproduces within its erstwhile predators, environmental amoeba, by subverting the normal pathway of phagocytosis and degradation. The molecular mechanisms which confer resistance to amoeba are apparently conserved and also allow replication within macrophages. Thus, L. pneumophila can act as an ‘accidental’ human pathogen and cause a severe pneumonia known as Legionnaires’ disease. The intracellular localisation of L. pneumophila protects it from some antibiotics, and this fact must be taken into account to develop new anti-bacterial compounds. In addition, the intracellular lifestyle of L. pneumophila may render the bacteria susceptible to compounds diminishing bacterial virulence and decreasing intracellular survival and replication of this pathogen. The development of a single infection cycle intracellular replication assay using GFP-producing L. pneumophila and Acanthamoeba castellanii amoeba is reported here. This fluorescence-based assay allows for continuous monitoring of intracellular replication rates, revealing the effect of bacterial gene deletions or drug treatment. To examine how perturbations of the host cell affect L. pneumophila replication, several known host-targeting compounds were tested, including modulators of cytoskeletal dynamics, vesicle scission and Ras GTPase localisation. Our results reveal a hitherto unrealized potential antibiotic property of the β-lactone-based Ras depalmitoylation inhibitor palmostatin M, but not the closely related inhibitor palmostatin B. Further characterisation indicated that this compound caused specific growth inhibition of Legionella and Mycobacterium species, suggesting that it may act on a common bacterial target. PMID:24058631

  16. Proteomic characterization of the subpellicular cytoskeleton of Toxoplasma gondii tachyzoites.

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    Gómez de León, Carmen T; Díaz Martín, Rubén Darío; Mendoza Hernández, Guillermo; González Pozos, Sirenia; Ambrosio, Javier R; Mondragón Flores, Ricardo

    2014-12-05

    Toxoplasma, the causative agent of toxoplasmosis in animals and humans, has a subpellicular cytoskeleton that is involved in motility, cell shape and invasion. Knowledge of components of the cytoskeleton is necessary to understand the invasion mechanisms as well as for the identification of possible therapeutic targets. To date, most cytoskeletal components of Toxoplasma remain unidentified due mainly to the lack of reproducible methods for their isolation. Based on the successful isolation of the cytoskeleton, it was possible to report for the first time, the proteomic characterization of the subpellicular cytoskeleton of Toxoplasma formed by 95 cytoskeletal proteins through proteomic analysis by tandem mass spectrometry of one dimension SDS PAGE. By bioinformatic analysis of the data, proteins were classified as: 18 conventional cytoskeletal proteins; 10 inner membrane complex proteins, including 7 with alveolin repeats; 5 new proteins with alveolin like repeats; 37 proteins associated with other organelles and 25 novel proteins of unknown function. One of the alveolin like proteins not previously described in Toxoplasma named TgArticulin was partially characterized with a specific monoclonal antibody. Presence of TgArticulin was exclusively associated with the cytoskeleton fraction with a cortical distribution. Functions for the several molecules identified are proposed. This manuscript describes, for the first time, the proteome of the subpellicular cytoskeleton of Toxoplasma gondii. The importance of this study is related to the role of the cytoskeleton in the highly invasive capability of a parasite that causes abortion, blindness, and death by encephalitis in immunocompromised patients. Proteomic characterization of the cytoskeleton of T. gondii tachyzoites was possible by the development of a successful procedure for the isolation of the subpellicular cytoskeleton. Knowledge of the composition of the cytoskeleton of Toxoplasma is fundamental for the

  17. Toxoplasma DJ-1 Regulates Organelle Secretion by a Direct Interaction with Calcium-Dependent Protein Kinase 1

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    Child, Matthew A.; Garland, Megan; Foe, Ian; Madzelan, Peter; Treeck, Moritz; van der Linden, Wouter A.; Oresic Bender, Kristina; Weerapana, Eranthie; Wilson, Mark A.; Boothroyd, John C.; Reese, Michael L.

    2017-01-01

    ABSTRACT Human DJ-1 is a highly conserved and yet functionally enigmatic protein associated with a heritable form of Parkinson’s disease. It has been suggested to be a redox-dependent regulatory scaffold, binding to proteins to modulate their function. Here we present the X-ray crystal structure of the Toxoplasma orthologue Toxoplasma gondii DJ-1 (TgDJ-1) at 2.1-Å resolution and show that it directly associates with calcium-dependent protein kinase 1 (CDPK1). The TgDJ-1 structure identifies an orthologously conserved arginine dyad that acts as a phospho-gatekeeper motif to control complex formation. We determined that the binding of TgDJ-1 to CDPK1 is sensitive to oxidation and calcium, and that this interaction potentiates CDPK1 kinase activity. Finally, we show that genetic deletion of TgDJ-1 results in upregulation of CDPK1 expression and that disruption of the CDPK1/TgDJ-1 complex in vivo prevents normal exocytosis of parasite virulence-associated organelles called micronemes. Overall, our data suggest that TgDJ-1 functions as a noncanonical kinase-regulatory scaffold that integrates multiple intracellular signals to tune microneme exocytosis in T. gondii. PMID:28246362

  18. Toxoplasma gondii gamma irradiation using Co-60

    International Nuclear Information System (INIS)

    Serra-Freire, Nicolau Maues

    1996-01-01

    The use of nuclear power through radiation for the destruction of microorganisms which cause food deterioration, infections and toxicosis, is specifically for peaceful purposes. Toxoplasma gondii is a protozoa responsible for illnesses in humans and animals. One of the most common ways of transmission is through raw or poorly cooked meat. There is little information on the resistance of T. gondii to radiation. The objective of this research is to determine the Minimum Lethal Dose (MLD) of gamma radiation for those microorganisms. Suspensions of T. gondii containing approximately one million taquizoites/ml were irradiated with doses between up 0,01 up to 0,15 kGy (Kilogray) and inoculated to mice. The surviving T. gondii were re-irradiated with 0,01 up to 0,16 kGy. The irradiated protozoa were totally destroyed with a 0,15 kGy dose (MLD). Taquizoites issued from live protozoa of 0,14 kGy also were completely destroyed with dose of 0,15 kGy. No increase in resistance was observed regarding the non irradiated protozoa. (author)

  19. Antiretroviral activity of protease inhibitors against Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Lianet Monzote

    2013-02-01

    Full Text Available The introduction of highly active antiretroviral therapy (HAART has caused a marked reduction in the occurrence and severity of parasitic infections, including the toxoplasmic encephalitis (TE. These changes have been attributed to the restoration of cell-mediated immunity. This study was developed to examine the activity of six antiretroviral protease inhibitors (API on Toxoplasma gondii tachyzoites. The six API showed anti-Toxoplasma activity, with IC50 value between 1.4 and 6.6 µg/mL. Further studies at the molecular level should be performed to clarify if the use of API could be beneficial or not for AIDS patients with TE.

  20. Cationic Antimicrobial Peptide LL-37 Is Effective against both Extra- and Intracellular Staphylococcus aureus

    Science.gov (United States)

    Noore, Jabeen; Noore, Adly

    2013-01-01

    The increasing resistance of bacteria to conventional antibiotics and the challenges posed by intracellular bacteria, which may be responsible for chronic and recurrent infections, have driven the need for advanced antimicrobial drugs for effective elimination of both extra- and intracellular pathogens. The purpose of this study was to determine the killing efficacy of cationic antimicrobial peptide LL-37 compared to conventional antibiotics against extra- and intracellular Staphylococcus aureus. Bacterial killing assays and an infection model of osteoblasts and S. aureus were studied to determine the bacterial killing efficacy of LL-37 and conventional antibiotics against extra- and intracellular S. aureus. We found that LL-37 was effective in killing extracellular S. aureus at nanomolar concentrations, while lactoferricin B was effective at micromolar concentrations and doxycycline and cefazolin at millimolar concentrations. LL-37 was surprisingly more effective in killing the clinical strain than in killing an ATCC strain of S. aureus. Moreover, LL-37 was superior to conventional antibiotics in eliminating intracellular S. aureus. The kinetic studies further revealed that LL-37 was fast in eliminating both extra- and intracellular S. aureus. Therefore, LL-37 was shown to be very potent and prompt in eliminating both extra- and intracellular S. aureus and was more effective in killing extra- and intracellular S. aureus than commonly used conventional antibiotics. LL-37 could potentially be used to treat chronic and recurrent infections due to its effectiveness in eliminating not only extracellular but also intracellular pathogens. PMID:23274662

  1. Genomic data reveal Toxoplasma gondii differentiation mutants are also impaired with respect to switching into a novel extracellular tachyzoite state.

    Directory of Open Access Journals (Sweden)

    Pamela J Lescault

    2010-12-01

    Full Text Available Toxoplasma gondii pathogenesis includes the invasion of host cells by extracellular parasites, replication of intracellular tachyzoites, and differentiation to a latent bradyzoite stage. We present the analysis of seven novel T. gondii insertional mutants that do not undergo normal differentiation to bradyzoites. Microarray quantification of the variation in genome-wide RNA levels for each parasite line and times after induction allowed us to describe states in the normal differentiation process, to analyze mutant lines in the context of these states, and to identify genes that may have roles in initiating the transition from tachyzoite to bradyzoite. Gene expression patterns in wild-type parasites undergoing differentiation suggest a novel extracellular state within the tachyzoite stage. All mutant lines exhibit aberrant regulation of bradyzoite gene expression and notably some of the mutant lines appear to exhibit high proportions of the intracellular tachyzoite state regardless of whether they are intracellular or extracellular. In addition to the genes identified by the insertional mutagenesis screen, mixture model analysis allowed us to identify a small number of genes, in mutants, for which expression patterns could not be accounted for using the three parasite states--genes that may play a mechanistic role in switching from the tachyzoite to bradyzoite stage.

  2. SPORULATION AND SURVIVAL OF TOXOPLASMA GONDII OOCYSTS IN SEA WATER

    Science.gov (United States)

    Since 1992, we have been collaborating in studies on southern sea otters (Enhdyra lutris nereis) as part of a program to define factors which may be responsible for limiting the growth of the southern sea otter population. We previously demonstrated Toxoplasma gondii in sea otter...

  3. Anti- toxoplasma gondii activity of constituents from Balsamocitrus ...

    African Journals Online (AJOL)

    Isolation, characterization and anti-Toxoplasma gondii activity of constituents from the CH2Cl2/MeOH (1/1) extract of the roots of the cameroonian plant Balsamocitrus camerunensis L. were investigated in this study. Four known coumarins derivatives were isolated, namely, marmin (1), imperatorin (2), xanthoxyletin (3), ...

  4. A biocoagulant slow sand filtration for disinfection of Toxoplasma ...

    African Journals Online (AJOL)

    An integrated low-tech biocoagulant-sand filter drum for disinfection of oocysts of Toxoplasma gondii targeted for developing countries was evaluated. Dirty and turbid water (130.3 NTU) from Mezam River and leachates from dump sites and stagnant water in Bamenda, Cameroon, was analyzed microscopically after ...

  5. Antibodies to Toxoplasma gondii in Backyard and Roaming Pigs ...

    African Journals Online (AJOL)

    Toxoplasma gondii, the etiologic agent of Toxoplasmosis, can be transmitted to pigs through the ingestion of oocysts, and to humans through consumption of pork containing viable cysts causing neonatal deaths and abortion in animals, and opportunistic infections in immunocompromised humans. The objective of this ...

  6. Prevalence of Toxoplasma gondii in common moles (Talpa europaea)

    NARCIS (Netherlands)

    Krijger, I.M.; Cornelissen, J.B.W.J.; Wisselink, H.J.; Meerburg, B.G.

    2014-01-01

    Background The prevalence of Toxoplasma gondii in common moles, Talpa europaea, was investigated in order to determine whether moles can serve as an indicator species for T. gondii infections in livestock. Findings In total, 86 moles were caught from 25 different sites in the Netherlands. Five

  7. Toxoplasma gondii decreases the reproductive fitness in mice

    Czech Academy of Sciences Publication Activity Database

    Dvořáková-Hortová, K.; Šídlová, A.; Děd, Lukáš; Hladovcová, D.; Vieweg, M.; Weidner, W.; Steger, K.; Stopka, P.; Paradowska-Dogan, A.

    2014-01-01

    Roč. 9, č. 6 (2014), s. 1-11 E-ISSN 1932-6203 R&D Projects: GA MŠk(CZ) ED1.1.00/02.0109 Institutional support: RVO:86652036 Keywords : Toxoplasma gondii * reproductive fitness * DNA methylation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 3.234, year: 2014

  8. Toxoplasma gondii seroprevalence in dairy and beef cattle

    DEFF Research Database (Denmark)

    Jokelainen, Pikka; Tagel, Maarja; Motus, Kerli

    2017-01-01

    Toxoplasma gondii is a zoonotic protozoan parasite that thrives in Estonia. In this nationwide cross-sectional study, we tested sera from 3991 cattle, collected from 228 farms in 2012–2013, for anti-T. gondii immunoglobulin G antibodies using a commercial direct agglutination test. Titer of 100 w...

  9. Toxoplasma gondii seroprevalence in breeding pigs in Estonia

    DEFF Research Database (Denmark)

    Santoro, Azzurra; Tagel, Maarja; Must, Kärt

    2017-01-01

    Background: Toxoplasma gondii is a widespread occurring parasite infecting warm-blooded animals, including pigs and humans. The aims of this study were to estimate the prevalence of anti-T. gondii antibodies and to evaluate risk factors for T. gondii seropositivity in breeding pigs raised in Esto...

  10. Sero-prevalence of Toxoplasma gondii in Danish pigs

    DEFF Research Database (Denmark)

    Kofoed, Kristina Grønbech; Vorslund-Kiær, Mia; Nielsen, Henrik Vedel

    2017-01-01

    In 2015, the World Health Organisation rated toxoplasmosis as one of the most important food borne zoonotic diseases in the world. In addition, recent studies have associated Toxoplasma gondii sero-positivity with severe mental illnesses such as schizophrenia. Intake of raw or insufficiently cooked...

  11. The neurotropic parasite Toxoplasma gondii increases dopamine metabolism

    Science.gov (United States)

    The common parasite Toxoplasma gondii induces behavioral alterations in its hosts including phenotypes increasing the likelihood of its transmission in rodents and reports of psychobehavioral alterations in humans. We have found that elevated levels of dopamine are associated with the encysted stage...

  12. Toxoplasma gondii impairs memory in infected seniors.

    Science.gov (United States)

    Gajewski, Patrick D; Falkenstein, Michael; Hengstler, Jan G; Golka, Klaus

    2014-02-01

    Almost 30% of humans present a Toxoplasma gondii positive antibody status and its prevalence increases with age. The central nervous system is the main target. However, little is known about the influence of asymptomatic i.e. latent Toxoplasmosis on cognitive functions in humans. To investigate neurocognitive dysfunctions in asymptomatic older adults with T. gondii positive antibody status a double-blinded neuropsychological study was conducted. The participants were classified from a population-based sample (N=131) of healthy participants with an age of 65 years and older into two groups with 42 individuals each: Toxoplasmosis positive (T-pos; IgG>50 IU/ml) and Toxoplasmosis negative (T-neg; IgG=0 IU/ml). The outcome measures were a computer-based working-memory test (2-back) and several standardized psychometric tests of memory and executive cognitive functions. T-pos seniors showed an impairment of different aspects of memory. The rate of correctly detected target symbols in a 2-back task was decreased by nearly 9% (P=0.020), corresponding to a performance reduction of about 35% in working memory relative to the T-neg group. Moreover, T-pos seniors had a lower performance in a verbal memory test, both regarding immediate recall (10% reduction; P=0.022), delayed recognition (6%; P=0.037) and recall from long-term memory assessed by the word fluency tests (12%; P=0.029). In contrast, executive functions were not affected. The effects remained mostly unchanged after controlling for medication. The impairment of memory functions in T-pos seniors was accompanied by a decreased self-reported quality of life. Because of the high prevalence of asymptomatic Toxoplasmosis and an increasing population of older adults this finding is of high relevance for public health. Copyright © 2013 Elsevier Inc. All rights reserved.

  13. Stochastic models of intracellular transport

    KAUST Repository

    Bressloff, Paul C.; Newby, Jay M.

    2013-01-01

    mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually

  14. TOXOPLASMA AND VIRAL ANTIBODIES AMONG HIV PATIENTS AND INMATES IN CENTRAL JAVA, INDONESIA.

    Science.gov (United States)

    Sari, Yulia; Haryati, Sri; Raharjo, Irvan; Prasetyo, Afiono Agung

    2015-11-01

    In Indonesia, Toxoplasma and its associations with blood-borne viruses have been poorly studied. In order to study the association between anti-Toxoplasma antibodies and blood-borne viral antibodies, blood samples from 497 participants (375 inmates from four prisons in Central Java, Indonesia and 122 HIV patients at a Voluntary Counseling and Testing Clinic in Surakarta, Indonesia) were tested for serological markers of Toxoplasma, human immunodeficiency virus (HIV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and human T-lymphotropic virus types I and II (HTLV-1/2). Anti-Toxoplasma IgG and IgM positivity rates were 41.6% and 3.6%, respectively. One point two percent of participants was positive for both anti-Toxoplasma IgG and IgM antibodies. Sixteen point five percent, 11.3%, 2.6% and 2.8% of participants were positive for anti- Toxoplasma IgG combined with anti-HCV antibodies, anti-Toxoplasma IgG combined with anti-HIV antibodies, anti-Toxoplasma IgM combined with anti-HIV antibodes and anti-Toxoplasma IgG combined with both anti-HIV and anti-HCV antibodies, respectively. Anti-Toxoplasma IgM seropositivity was associated with anti-HIV (aOR = 4.3; 95% CI: 1.112-16.204, p = 0.034). Anti-Toxoplasma IgG antibodies were associated with anti-HCV (aOR = 2.8; 95% CI: 1.749-4.538, p < 0.001) and history of injection drug use (aOR = 3.1; 95% CI: 1.905-5.093, p < 0.001). In conclusion, we recommend patients with HIV, HCV infection and injection drug users should be screened for Toxoplasma infection in Indonesia.

  15. Morbillivirus and Toxoplasma exposure and association with hematological parameters for southern Beaufort Sea polar bears: potential response to infectious agents in a sentinel species

    Science.gov (United States)

    Kirk, Cassandra M.; Amstrup, Steven C.; Swor, Rhonda; Holcomb, Darce; O'Hara, Todd M.

    2010-01-01

    Arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing conditions. Declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. As food webs change and human activities respond to a milder Arctic, exposure of polar bears and other arctic marine organisms to infectious agents may increase. Because of the polar bear’s status as arctic ecosystem sentinel, polar bear health could provide an index of changing pathogen occurrence throughout the Arctic, however, exposure and monitoring protocols have yet to be established. We examine prevalence of antibodies to Toxoplasma gondii, and four morbilliviruses (canine distemper [CDV], phocine distemper [PDV], dolphin morbillivirus [DMV], porpoise morbillivirus [PMV]) including risk factors for exposure. We also examine the relationships between antibody levels and hematologic values established in the previous companion article. Antibodies to Toxoplasma gondii and morbilliviruses were found in both sample years. We found a significant inverse relationship between CDV titer and total leukocytes, neutrophils, monocytes, and eosinophils, and a significant positive relationship between eosinophils and Toxoplasma gondii antibodies. Morbilliviral prevalence varied significantly among age cohorts, with 1–2 year olds least likely to be seropositive and bears aged 5–7 most likely. Data suggest that the presence of CDV and Toxoplasma gondii antibodies is associated with polar bear hematologic values. We conclude that exposure to CDV-like antigen is not randomly distributed among age classes and suggest that differing behaviors among life history stages may drive probability of specific antibody presence.

  16. Morbillivirus and Toxoplasma exposure and association with hematological parameters for southern Beaufort Sea polar bears: potential response to infectious agents in a sentinel species.

    Science.gov (United States)

    Kirk, Cassandra M; Amstrup, Steven; Swor, Rhonda; Holcomb, Darce; O'Hara, Todd M

    2010-09-01

    Arctic temperatures are increasing in response to greenhouse gas forcing and polar bears have already responded to changing conditions. Declines in body stature and vital rates have been linked to warming-induced loss of sea-ice. As food webs change and human activities respond to a milder Arctic, exposure of polar bears and other arctic marine organisms to infectious agents may increase. Because of the polar bear's status as arctic ecosystem sentinel, polar bear health could provide an index of changing pathogen occurrence throughout the Arctic, however, exposure and monitoring protocols have yet to be established. We examine prevalence of antibodies to Toxoplasma gondii, and four morbilliviruses (canine distemper [CDV], phocine distemper [PDV], dolphin morbillivirus [DMV], porpoise morbillivirus [PMV]) including risk factors for exposure. We also examine the relationships between antibody levels and hematologic values established in the previous companion article. Antibodies to Toxoplasma gondii and morbilliviruses were found in both sample years. We found a significant inverse relationship between CDV titer and total leukocytes, neutrophils, monocytes, and eosinophils, and a significant positive relationship between eosinophils and Toxoplasma gondii antibodies. Morbilliviral prevalence varied significantly among age cohorts, with 1-2 year olds least likely to be seropositive and bears aged 5-7 most likely. Data suggest that the presence of CDV and Toxoplasma gondii antibodies is associated with polar bear hematologic values. We conclude that exposure to CDV-like antigen is not randomly distributed among age classes and suggest that differing behaviors among life history stages may drive probability of specific antibody presence.

  17. Purification and proteomics of pathogen-modified vacuoles and membranes

    Directory of Open Access Journals (Sweden)

    Jo-Ana eHerweg

    2015-06-01

    Full Text Available Certain pathogenic bacteria adopt an intracellular lifestyle and proliferate in eukaryotic host cells. The intracellular niche protects the bacteria from cellular and humoral components of the mammalian immune system, and at the same time, allows the bacteria to gain access to otherwise restricted nutrient sources. Yet, intracellular protection and access to nutrients comes with a price, i.e. the bacteria need to overcome cell-autonomous defense mechanisms, such as the bactericidal endocytic pathway. While a few bacteria rupture the early phagosome and escape into the host cytoplasm, most intracellular pathogens form a distinct, degradation-resistant and replication-permissive membranous compartment. Intracellular bacteria that form unique pathogen vacuoles include Legionella, Mycobacterium, Chlamydia, Simkania and Salmonella species. In order to understand the formation of these pathogen niches on a global scale and in a comprehensive and quantitative manner, an inventory of compartment-associated host factors is required. To this end, the intact pathogen compartments need to be isolated, purified and biochemically characterized. Here, we review recent progress on the isolation and purification of pathogen-modified vacuoles and membranes, as well as their proteomic characterization by mass spectrometry and different validation approaches. These studies provide the basis for further investigations on the specific mechanisms of pathogen-driven compartment formation.

  18. Sexual transmission of Toxoplasma gondii in sheep.

    Science.gov (United States)

    Lopes, Welber Daniel Zanetti; Rodriguez, Joana D'Ark; Souza, Fernando A; dos Santos, Thais Rabelo; dos Santos, Ricardo Silva; Rosanese, Walter Matheus; Lopes, Werik Renato Zanetti; Sakamoto, Cláudio Alessandro; da Costa, Alvimar José

    2013-07-01

    Male sheep of reproductive age were distributed into three groups: GI, a sheep inoculated (oral) with 2.0×10(5) oocysts of the P strain of Toxoplasma gondii; GII, a sheep infected (subcutaneous) with 1.0×10(6) tachyzoites of the RH strain of T. gondii; and GIII, a sheep kept as a control (not infected). After the inoculation of the males, 12 breeding ewes, which were not pregnant and which were serologically negative for reproductive diseases (particularly toxoplasmosis), were distributed into three groups, synchronized, and subsequently exposed to natural mating with previously inoculated males. The distribution was as follows: five ewes that underwent natural mating with the GI male, five ewes that were exposed to natural mating with the GII male, and two ewes that were mated with the non-infected male (control). Serum samples of all the ewes were collected on days -30, -14, -7, -1, and 0 (days before natural mating) and on days 1, 3, 5, 7, 11, 14, and weekly until birth; the presence of serum antibodies against T. gondii was assessed by IFAT. Using a bioassay and PCR, T. gondii was isolated from the semen of the infected reproducing sheep before mating. Following natural mating, 5 of the 12 females displayed antibodies specific for T. gondii; of these animals, two of the ewes underwent natural mating with the male inoculated with oocysts (GI) and three with the male infected with tachyzoites (GII). One of the females that displayed antibodies specific to this coccidian and that underwent natural mating with the GII sheep had a macerated fetus on the 70th day following coverage. Using a bioassay after the birth, it was possible to isolate T. gondii from samples of the "pool" of tissues from the five females that seroconverted after natural mating and from their respective lambs. Using PCR, the DNA of T. gondii was isolated from the "pool" of tissues from one and two females exposed to natural mating with the reproductive males infected with the oocysts and

  19. Seroprevalence of Toxoplasma gondii in humans and pigs in North Sulawesi, Indonesia.

    Science.gov (United States)

    Tuda, Josef; Adiani, Sri; Ichikawa-Seki, Madoka; Umeda, Kousuke; Nishikawa, Yoshifumi

    2017-10-01

    Toxoplasma gondii, an intracellular protozoan parasite, is a major public health concern throughout the world. Importantly, toxoplasmosis has several adverse effects, including neurological and ocular diseases. There are currently no data on the prevalence of T. gondii infection in humans or animals in North Sulawesi, although Indonesia is known to have a high seroprevalence of this parasite. In this study, the prevalence of T. gondii was determined in samples of humans and pigs from North Sulawesi using the latex agglutination test. In total, 856 human were sampled and 58.5% of whom were positive for T. gondii. Although the antibody prevalence in male and female children aged 0-9years was 40% in both sexes, suggesting that the transmission rate of the parasite to humans is extremely high in this area. However, the overall prevalence of T. gondii in pigs was only 2.3%. Our study indicates a high incidence of T. gondii infection in humans. Therefore, a survey of the prevalence of T. gondii among different infection sources is required to determine the major risk factors for infection in North Sulawesi. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Characterization of Toxoplasma DegP, a rhoptry serine protease crucial for lethal infection in mice.

    Directory of Open Access Journals (Sweden)

    Gaelle Lentini

    Full Text Available During the infection process, Apicomplexa discharge their secretory organelles called micronemes, rhoptries and dense granules to sustain host cell invasion, intracellular replication and to modulate host cell pathways and immune responses. Herein, we describe the Toxoplasma gondii Deg-like serine protein (TgDegP, a rhoptry protein homologous to High temperature requirement A (HtrA or Deg-like family of serine proteases. TgDegP undergoes processing in both types I and II strains as most of the rhoptries proteins. We show that genetic disruption of the degP gene does not impact the parasite lytic cycle in vitro but affects virulence in mice. While in a type I strain DegPI appears dispensable for the establishment of an infection, removal of DegPII in a type II strain dramatically impairs the virulence. Finally, we show that KO-DegPII parasites kill immunodeficient mice as efficiently as the wild-type strain indicating that the protease might be involved in the complex crosstalk that the parasite engaged with the host immune response. Thus, this study unravels a novel rhoptry protein in T. gondii important for the establishment of lethal infection.

  1. The apical complex provides a regulated gateway for secretion of invasion factors in Toxoplasma.

    Directory of Open Access Journals (Sweden)

    Nicholas J Katris

    2014-04-01

    Full Text Available The apical complex is the definitive cell structure of phylum Apicomplexa, and is the focus of the events of host cell penetration and the establishment of intracellular parasitism. Despite the importance of this structure, its molecular composition is relatively poorly known and few studies have experimentally tested its functions. We have characterized a novel Toxoplasma gondii protein, RNG2, that is located at the apical polar ring--the common structural element of apical complexes. During cell division, RNG2 is first recruited to centrosomes immediately after their duplication, confirming that assembly of the new apical complex commences as one of the earliest events of cell replication. RNG2 subsequently forms a ring, with the carboxy- and amino-termini anchored to the apical polar ring and mobile conoid, respectively, linking these two structures. Super-resolution microscopy resolves these two termini, and reveals that RNG2 orientation flips during invasion when the conoid is extruded. Inducible knockdown of RNG2 strongly inhibits host cell invasion. Consistent with this, secretion of micronemes is prevented in the absence of RNG2. This block, however, can be fully or partially overcome by exogenous stimulation of calcium or cGMP signaling pathways, respectively, implicating the apical complex directly in these signaling events. RNG2 demonstrates for the first time a role for the apical complex in controlling secretion of invasion factors in this important group of parasites.

  2. Host Mitochondrial Association Evolved in the Human Parasite Toxoplasma gondii via Neofunctionalization of a Gene Duplicate.

    Science.gov (United States)

    Adomako-Ankomah, Yaw; English, Elizabeth D; Danielson, Jeffrey J; Pernas, Lena F; Parker, Michelle L; Boulanger, Martin J; Dubey, Jitender P; Boyle, Jon P

    2016-05-01

    In Toxoplasma gondii, an intracellular parasite of humans and other animals, host mitochondrial association (HMA) is driven by a gene family that encodes multiple mitochondrial association factor 1 (MAF1) proteins. However, the importance of MAF1 gene duplication in the evolution of HMA is not understood, nor is the impact of HMA on parasite biology. Here we used within- and between-species comparative analysis to determine that the MAF1 locus is duplicated in T. gondii and its nearest extant relative Hammondia hammondi, but not another close relative, Neospora caninum Using cross-species complementation, we determined that the MAF1 locus harbors multiple distinct paralogs that differ in their ability to mediate HMA, and that only T. gondii and H. hammondi harbor HMA(+) paralogs. Additionally, we found that exogenous expression of an HMA(+) paralog in T. gondii strains that do not normally exhibit HMA provides a competitive advantage over their wild-type counterparts during a mouse infection. These data indicate that HMA likely evolved by neofunctionalization of a duplicate MAF1 copy in the common ancestor of T. gondii and H. hammondi, and that the neofunctionalized gene duplicate is selectively advantageous. Copyright © 2016 by the Genetics Society of America.

  3. MYR1-Dependent Effectors Are the Major Drivers of a Host Cell's Early Response to Toxoplasma, Including Counteracting MYR1-Independent Effects.

    Science.gov (United States)

    Naor, Adit; Panas, Michael W; Marino, Nicole; Coffey, Michael J; Tonkin, Christopher J; Boothroyd, John C

    2018-04-03

    The obligate intracellular parasite Toxoplasma gondii controls its host cell from within the parasitophorous vacuole (PV) by using a number of diverse effector proteins, a subset of which require the aspartyl protease 5 enzyme (ASP5) and/or the recently discovered MYR1 protein to cross the PV membrane. To examine the impact these effectors have in the context of the entirety of the host response to Toxoplasma , we used RNA-Seq to analyze the transcriptome expression profiles of human foreskin fibroblasts infected with wild-type RH (RH-WT), RHΔ myr1 , and RHΔ asp5 tachyzoites. Interestingly, the majority of the differentially regulated genes responding to Toxoplasma infection are MYR1 dependent. A subset of MYR1 responses were ASP5 independent, and MYR1 function did not require ASP5 cleavage, suggesting the export of some effectors requires only MYR1. Gene set enrichment analysis of MYR1-dependent host responses suggests an upregulation of E2F transcription factors and the cell cycle and a downregulation related to interferon signaling, among numerous others. Most surprisingly, "hidden" responses arising in RHΔ myr1 - but not RH-WT-infected host cells indicate counterbalancing actions of MYR1-dependent and -independent activities. The host genes and gene sets revealed here to be MYR1 dependent provide new insight into the parasite's ability to co-opt host cell functions. IMPORTANCE Toxoplasma gondii is unique in its ability to successfully invade and replicate in a broad range of host species and cells within those hosts. The complex interplay of effector proteins exported by Toxoplasma is key to its success in co-opting the host cell to create a favorable replicative niche. Here we show that a majority of the transcriptomic effects in tachyzoite-infected cells depend on the activity of a novel translocation system involving MYR1 and that the effectors delivered by this system are part of an intricate interplay of activators and suppressors. Removal of all MYR1

  4. Insecticide resistance and intracellular proteases.

    Science.gov (United States)

    Wilkins, Richard M

    2017-12-01

    Pesticide resistance is an example of evolution in action with mechanisms of resistance arising from mutations or increased expression of intrinsic genes. Intracellular proteases have a key role in maintaining healthy cells and in responding to stressors such as pesticides. Insecticide-resistant insects have constitutively elevated intracellular protease activity compared to corresponding susceptible strains. This increase was shown for some cases originally through biochemical enzyme studies and subsequently putatively by transcriptomics and proteomics methods. Upregulation and expression of proteases have been characterised in resistant strains of some insect species, including mosquitoes. This increase in proteolysis results in more degradation products (amino acids) of intracellular proteins. These may be utilised in the resistant strain to better protect the cell from stress. There are changes in insect intracellular proteases shortly after insecticide exposure, suggesting a role in stress response. The use of protease and proteasome inhibitors or peptide mimetics as synergists with improved application techniques and through protease gene knockdown using RNA interference (possibly expressed in crop plants) may be potential pest management strategies, in situations where elevated intracellular proteases are relevant. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

  5. Serosurvey for Leishmania spp., Toxoplasma gondii, Trypanosoma cruzi and Neospora caninum in neighborhood dogs in Curitiba-Paraná, Brazil

    Directory of Open Access Journals (Sweden)

    Caroline Constantino

    Full Text Available Abstract Neighborhood dogs may act as reservoirs for several zoonotic protozoan infections, particularly in urban areas, thus constituting a potential public health threat. Accordingly, the aim of the present study was to evaluate the exposure of neighborhood dogs to four protozoan pathogens in public areas with high levels of human movement in Curitiba, southern Brazil. Blood samples from 26 neighborhood dogs were screened by means of the indirect immunofluorescent antibody test (IFAT for Leishmania spp., Toxoplasma gondii, Trypanosoma cruzi and Neospora caninum, and a questionnaire was answered by the respective keeper. A total of 8/26 dogs (30.7% seroreactive to T. gondii, 3/26 (11.5% to N. caninum and 2/26 (7.7% to both were identified. All the samples were seronegative for T. cruzi and Leishmania spp. Pathogen seroreactivity was not associated with the daily human movements or other epidemiological variables investigated (p > 0.05. In conclusion, the low seroprevalence for T. gondii and N. caninum indicated low environmental and food risk for animal infection and the seronegativity for Leishmania spp. and T. cruzi may reflect the absence of these pathogens in urban areas of Curitiba. Moreover, neighborhood dogs may be used as environmental sentinels for the presence of protozoan pathogens and their vectors.

  6. Hydrologic and Vegetative Removal of Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii Surrogate Microspheres in Coastal Wetlands

    Science.gov (United States)

    Hogan, Jennifer N.; Daniels, Miles E.; Watson, Fred G.; Oates, Stori C.; Miller, Melissa A.; Conrad, Patricia A.; Shapiro, Karen; Hardin, Dane; Dominik, Clare; Melli, Ann; Jessup, David A.

    2013-01-01

    Constructed wetland systems are used to reduce pollutants and pathogens in wastewater effluent, but comparatively little is known about pathogen transport through natural wetland habitats. Fecal protozoans, including Cryptosporidium parvum, Giardia lamblia, and Toxoplasma gondii, are waterborne pathogens of humans and animals, which are carried by surface waters from land-based sources into coastal waters. This study evaluated key factors of coastal wetlands for the reduction of protozoal parasites in surface waters using settling column and recirculating mesocosm tank experiments. Settling column experiments evaluated the effects of salinity, temperature, and water type (“pure” versus “environmental”) on the vertical settling velocities of C. parvum, G. lamblia, and T. gondii surrogates, with salinity and water type found to significantly affect settling of the parasites. The mesocosm tank experiments evaluated the effects of salinity, flow rate, and vegetation parameters on parasite and surrogate counts, with increased salinity and the presence of vegetation found to be significant factors for removal of parasites in a unidirectional transport wetland system. Overall, this study highlights the importance of water type, salinity, and vegetation parameters for pathogen transport within wetland systems, with implications for wetland management, restoration efforts, and coastal water quality. PMID:23315738

  7. Sexual reproduction and the evolution of microbial pathogens.

    Science.gov (United States)

    Heitman, Joseph

    2006-09-05

    Three common systemic human fungal pathogens--Cryptococcus neoformans, Candida albicans and Aspergillus fumigatus--have retained all the machinery to engage in sexual reproduction, and yet their populations are often clonal with limited evidence for recombination. Striking parallels have emerged with four protozoan parasites that infect humans: Toxoplasma gondii, Trypanosoma brucei, Trypanosoma cruzi and Plasmodium falciparum. Limiting sexual reproduction appears to be a common virulence strategy, enabling generation of clonal populations well adapted to host and environmental niches, yet retaining the ability to engage in sexual or parasexual reproduction and respond to selective pressure. Continued investigation of the sexual nature of microbial pathogens should facilitate both laboratory investigation and an understanding of the complex interplay between pathogens, hosts, vectors, and their environments.

  8. Pathogen intelligence

    Directory of Open Access Journals (Sweden)

    Michael eSteinert

    2014-01-01

    Full Text Available Different species inhabit different sensory worlds and thus have evolved diverse means of processing information, learning and memory. In the escalated arms race with host defense, each pathogenic bacterium not only has evolved its individual cellular sensing and behaviour, but also collective sensing, interbacterial communication, distributed information processing, joint decision making, dissociative behaviour, and the phenotypic and genotypic heterogeneity necessary for epidemiologic success. Moreover, pathogenic populations take advantage of dormancy strategies and rapid evolutionary speed, which allow them to save co-generated intelligent traits in a collective genomic memory. This review discusses how these mechanisms add further levels of complexity to bacterial pathogenicity and transmission, and how mining for these mechanisms could help to develop new anti-infective strategies.

  9. LOW PATHOGENIC POTENTIAL IN HETEROTROPHIC BACTERIA FROM POTABLE WATER

    Science.gov (United States)

    Forty-five isolates of HPC bacteria, most of which express virulence-related characteristics are being tested for pathogenicity in immunocompromised mice. All forty-five were negative for facultative intracellular pathogenicity. All twenty-three isolates tested thus far were a...

  10. Toxoplasma and Africa: One Parasite, Two Opposite Population Structures.

    Science.gov (United States)

    Galal, Lokman; Ajzenberg, Daniel; Hamidović, Azra; Durieux, Marie-Fleur; Dardé, Marie-Laure; Mercier, Aurélien

    2018-02-01

    Exploring the genetic diversity of Toxoplasma gondii is essential for an understanding of its worldwide distribution and the determinants of its evolution. Africa remains one of the least studied areas of the world regarding T. gondii genetic diversity. This review has compiled published data on T. gondii strains from Africa to generate a comprehensive map of their continent-wide geographical distribution. The emerging picture about T. gondii strain distribution in Africa suggests a geographical separation of the parasite populations across the continent. We discuss the potential role of a number of factors in shaping this structure. We finally suggest the next steps towards a better understanding of Toxoplasma epidemiology in Africa in light of the strains circulating on this continent. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Prevalence of Toxoplasma gondii in native donkeys in Mosul

    Directory of Open Access Journals (Sweden)

    Kh. J. Hussain

    2011-01-01

    Full Text Available The aim of the study was to determine the prevalence of Toxoplasma gondii in native donkeys in Mousl, Iraq. Fifty two sera (9 males and 43 females were examined by Latex agglutination test, Modified latex agglutination test with 2- mercaptoethanol test and Indirect ELISA test (Indirect IgG ELISA. The prevalence of Toxoplasma gondii in native donkeys was 46.15 %. Acute cases 8.33% and chronic cases 91.67 % when differentiated by Modified latex agglutination test with 2- mercaptoethanol test. The percentages of female and male infections were 51.16% (22/43 and 22.22% (2/9, respectively by using latex agglutination test, and the titeration of antibodies ranged between 1:20 - 1:1280 and for Indirect IgG ELISA it was 22.72% positive cases.

  12. Synthetic immunostimulatory glycans interference with host cell apoptosis upon of Toxoplasma gondii infection, in vitro

    Directory of Open Access Journals (Sweden)

    S.H. Eassa

    2017-06-01

    Full Text Available Toxoplasmosis is a protozoan infection of humans and animals caused by Toxoplasma gondii, and it’s continuous public health and food safety issue. The tachyzoites (Tg of T. gondii are the most important stage, as they come in direct contact with immune cells such as a macrophage. Tg can modulate and prevent apoptosis of immune cells while promoting survival of the pathogen. Infections caused by Tg can be eradicated if immune cells could stimulate apoptosis and kill pathogens upon exposure. Apoptosis is characterized by the release of mediators, namely Caspases (Cas. New means are required for inducing apoptosis and enhance immunity in the infected host cell to control toxoplasmosis. The present study investigated whether Synthetic Immuno-stimulatory Glycans (SIGs influence Cas and Nitric oxide (NO release and led to Tg damage. Galβ1-3Gal-PAA-fluor (SIG1, Fucα1-4GlcNAcβ-PAA-fluor (SIG2 and GlcNAcβ1-3GalNAcα-PAA-fluor (SIG3 constituted samples studied principally. Murine macrophage had been exposed to the Tg then the SIGs effects on Cas and NO production were determined after 20 hours of pathogen phagocytosis. Here we report that the SIGs had potent in vitro activity against T. gondii; SIG2 was more effective than SIG1 and SIG3, representative by SIG2 treated infected macrophages can induced infected macrophages to release Cas1, 3, and 9. Maximum production of NO by infected macrophages was noticed following the expoxure to all SIGs. Therefore the present study provided the method for the selection of SIGs ligands bearing immunostimulatory factor and apoptotic stimuli properties.

  13. Risk factors for Toxoplasma gondii infection in Kohat District, Pakistan

    OpenAIRE

    Gul Naila; Zareen Shehzad; Ur Rehman Faiz; Ur Rehman Hameed; Qayyum Sumbel; Khan Sumiya; Khan Feroz; Ali Khan Munsif; Saeed Kausar; Ayub Abid; Hayat Azam; Ateeq Muhammad; Ahmad Waqar

    2017-01-01

    Toxoplasma gondii is a widespread zoonotic parasite that is the causative agent for toxoplasmosis in human and completes its life cycle in separate hosts. Considering the significance of the infection, the current study was designed to asses to various risk factors for the parasite transmission to human in Kohat District, Pakistan. A total of 122 suspected individuals were asked to fill pre-designed questionnaire. A total of 44 (36.07%) individuals were found to be infected wit...

  14. Reproductive implications of exposure to Toxoplasma gondii and Neospora caninum in western grey kangaroos (Macropus fuliginosus ocydromus).

    Science.gov (United States)

    Mayberry, Chris; Maloney, Shane K; Mitchell, Jeff; Mawson, Peter R; Bencini, Roberta

    2014-04-01

    Australian marsupials are thought to be particularly vulnerable to pathologic impacts of Toxoplasma gondii, and they may be similarly affected by Neospora caninum. Pathology due to either organism could be expressed as reduced female reproductive performance. We studied adult female western grey kangaroos (Macropus fuliginosus ocydromus) from suburban Perth, Western Australia, between May 2006 and October 2008. We used indirect fluorescent antibody tests to look for evidence of exposure to T. gondii and N. caninum in M. fuliginosus ocydromus and tested the association between their reproductive performance and a positive test result. Although 20% of plasma samples collected from 102 female kangaroos were positive for T. gondii and 18% were positive for N. caninum, we found no association between positive results and reproductive performance. Further study will be required to clarify if, and under what circumstances, T. gondii and N. caninum are pathogenic to macropod marsupials.

  15. Exposure of free-living jaguars to Toxoplasma gondii, Neospora caninum and Sarcocystis neurona in the Brazilian Pantanal

    Directory of Open Access Journals (Sweden)

    Selma Samiko Miyazaki Onuma

    2014-12-01

    Full Text Available Toxoplasma gondii, Neospora caninum and Sarcocystis neurona are related apicomplexan parasites that cause reproductive and neurological disorders in a wide range of domestic and wild animals. In the present study, the immunofluorescence antibody test (IFAT was used to investigate the presence of antibodies against T. gondii, N. caninum and S. neurona in the sera of 11 free-living jaguars (Panthera onca in two protected areas in the Pantanal region of Mato Grosso state, Brazil. Ten jaguars (90.9% showed seropositivity for T. gondii, eight (72.7% for S. neurona, and seven (63.6% for N. caninum antigens. Our findings reveal exposure of jaguars to these related coccidian parasites and circulation of these pathogens in this wild ecosystem. To the best of our knowledge, this is the first serological detection of N. caninum and S. neurona in free-living jaguars.

  16. Exposure of free-living jaguars to Toxoplasma gondii, Neospora caninum and Sarcocystis neurona in the Brazilian Pantanal.

    Science.gov (United States)

    Onuma, Selma Samiko Miyazaki; Melo, Andréia Lima Tomé; Kantek, Daniel Luis Zanella; Crawshaw-Junior, Peter Gransden; Morato, Ronaldo Gonçalves; May-Júnior, Joares Adenílson; Pacheco, Thábata dos Anjos; Aguiar, Daniel Moura de

    2014-01-01

    Toxoplasma gondii, Neospora caninum and Sarcocystis neurona are related apicomplexan parasites that cause reproductive and neurological disorders in a wide range of domestic and wild animals. In the present study, the immunofluorescence antibody test (IFAT) was used to investigate the presence of antibodies against T. gondii, N. caninum and S. neurona in the sera of 11 free-living jaguars (Panthera onca) in two protected areas in the Pantanal region of Mato Grosso state, Brazil. Ten jaguars (90.9%) showed seropositivity for T. gondii, eight (72.7%) for S. neurona, and seven (63.6%) for N. caninum antigens. Our findings reveal exposure of jaguars to these related coccidian parasites and circulation of these pathogens in this wild ecosystem. To the best of our knowledge, this is the first serological detection of N. caninum and S. neurona in free-living jaguars.

  17. Prevalence of encysted Toxoplasma gondii in raptors from Alabama.

    Science.gov (United States)

    Lindsay, D S; Smith, P C; Hoerr, F J; Blagburn, B L

    1993-12-01

    Little is known about the prevalence of encysted Toxoplasma gondii in wild birds. We examined the hearts and breast muscles from 101 raptors for encysted T. gondii. All of the raptors had been submitted for necropsy to the State Veterinary Diagnostic Laboratory, Auburn, Alabama. Tissues were digested in acid-pepsin solution and inoculated into groups of 3-5 laboratory mice. Toxoplasma gondii was isolated from 27 of 101 (26.7%) raptors: 8 of 12 (66.7%) red-shouldered hawks (Buteo lineatus), 13 of 27 (41.1%) red-tailed hawks (Buteo jamaicensis), 1 of 4 (25%) Cooper's hawks (Accipiter cooperi), 1 of 5 (20%) great horned owls (Bubo virginianus), 4 of 15 (26.7%) barred owls (Strix varia), and 1 of 3 (33.3%) kestrels (Falco sparverius). Toxoplasma gondii was not isolated from 3 broad-winged hawks (Buteo platypterus), 3 sharp-shinned hawks (Accipiter striatus), 6 barn owls (Tyto alba), 9 screech owls (Asio otus), a Mississippi kite (Ictinia misisippiensis), 2 golden eagles (Aquila chrysaetos), a bald eagle (Haliaeetus leucocephalus), 4 ospreys (Pandion haliaetus), 4 turkey vultures (Cathartes aura), or 2 black vultures (Coragyps atratus). No significant difference (P > 0.05) in prevalence was detected based on sex using chi-square analysis. Chi-square analysis of the data demonstrated that adult raptors had encysted stages of T. gondii significantly (P < 0.05) more often than did immature raptors.

  18. Risk factors for Toxoplasma gondii infection in Kohat District, Pakistan

    Directory of Open Access Journals (Sweden)

    Gul Naila

    2017-01-01

    Full Text Available Toxoplasma gondii is a widespread zoonotic parasite that is the causative agent for toxoplasmosis in human and completes its life cycle in separate hosts. Considering the significance of the infection, the current study was designed to asses to various risk factors for the parasite transmission to human in Kohat District, Pakistan. A total of 122 suspected individuals were asked to fill pre-designed questionnaire. A total of 44 (36.07% individuals were found to be infected with Toxoplasma gondii. Handling pets and birds, untreated water, unpasteurized milk and undercooked meat were found to be associated with infection. Raw vegetables and blood transfusion were not found to be associated with infection in our study. Thus, it can be concluded that Toxoplasma gondiiis is a prevalent zoonotic agent in Kohat, Pakistan and various prophylactic measures like hand washing, cooking meat properly, wearing gloves while contacting pets and birds, treating water and pasteurizing milk will be very helpful to reduce disease burden in the study area.

  19. Tropism and pathogenicity of rickettsiae

    Directory of Open Access Journals (Sweden)

    Tsuneo eUchiyama

    2012-06-01

    Full Text Available Rickettsiae are obligate intracellular parasitic bacteria that cause febrile exanthematous illnesses such as Rocky Mountain spotted fever, Mediterranean spotted fever, epidemic and murine typhus, etc. Although the vector ranges of each Rickettsia species are rather restricted; i.e., ticks belonging to Arachnida and lice and fleas belonging to Insecta usually act as vectors for spotted fever group and typhus group rickettsiae, respectively, it would be interesting to elucidate the mechanisms controlling the vector tropism of rickettsiae. This review discusses the factors determining the vector tropism of rickettsiae. In brief, the vector tropism of rickettsiae species is basically consistent with their tropism towards cultured tick and insect cells. The mechanisms responsible for rickettsiae pathogenicity are also described. Recently, genomic analyses of rickettsiae have revealed that they possess several genes that are homologous to those affecting the pathogenicity of other bacteria. Analyses comparing the genomes of pathogenic and nonpathogenic strains of rickettsiae have detected many factors that are related to rickettsial pathogenicity. It is also known that a reduction in the rickettsial genome has occurred during the course of its evolution. Interestingly, Rickettsia species with small genomes, such as Rickettsia prowazekii, are more pathogenic to humans than those with larger genomes. This review also examines the growth kinetics of pathogenic and nonpathogenic species of spotted fever group rickettsiae in mammalian cells. The growth of nonpathogenic species is restricted in these cells, which is mediated, at least in part, by autophagy. The superinfection of nonpathogenic rickettsiae-infected cells with pathogenic rickettsiae results in an elevated yield of the nonpathogenic rickettsiae and the growth of the pathogenic rickettsiae. Autophagy is restricted in these cells. These results are discussed in this review.

  20. Subversion of inflammasome activation and pyroptosis by pathogenic bacteria

    Directory of Open Access Journals (Sweden)

    Larissa D Cunha

    2013-11-01

    Full Text Available Activation of the inflammasome occurs in response to a notably high number of pathogenic microbes and is a broad innate immune response that effectively contributes to restriction of pathogen replication and generation of adaptive immunity. Activation of these platforms leads to caspase-1- and/or caspase-11-dependent secretion of proteins, including cytokines, and induction of a specific form of cell death called pyroptosis, which directly or indirectly contribute for restriction of pathogen replication. Not surprisingly, bona fide intracellular pathogens developed strategies for manipulation of cell death to guarantee intracellular replication. In this sense, the remarkable advances in the knowledge of the inflammasome field have been accompanied by several reports characterizing the inhibition of this platform by several pathogenic bacteria. Herein, we review some processes used by pathogenic bacteria, including Yersinia spp., Pseudomonas aeruginosa, Vibrio parahaemolyticus, Chlamydia trachomatis, Francisella tularensis, Shigella flexneri, Legionella pneumophila and Coxiella burnetii to evade the activation of the inflammasome and the induction of pyroptosis.

  1. Lack of mitochondrial MutS homolog 1 in Toxoplasma gondii disrupts maintenance and fidelity of mitochondrial DNA and reveals metabolic plasticity.

    Directory of Open Access Journals (Sweden)

    Tamila Garbuz

    Full Text Available The importance of maintaining the fidelity of the mitochondrial genome is underscored by the presence of various repair pathways within this organelle. Presumably, the repair of mitochondrial DNA would be of particular importance in organisms that possess only a single mitochondrion, like the human pathogens Plasmodium falciparum and Toxoplasma gondii. Understanding the machinery that maintains mitochondrial DNA in these parasites is of particular relevance, as mitochondrial function is a validated and effective target for anti-parasitic drugs. We previously determined that the Toxoplasma MutS homolog TgMSH1 localizes to the mitochondrion. MutS homologs are key components of the nuclear mismatch repair system in mammalian cells, and both yeast and plants possess MutS homologs that localize to the mitochondria where they regulate DNA stability. Here we show that the lack of TgMSH1 results in accumulation of single nucleotide variations in mitochondrial DNA and a reduction in mitochondrial DNA content. Additionally, parasites lacking TgMSH1 function can survive treatment with the cytochrome b inhibitor atovaquone. While the Tgmsh1 knockout strain has several missense mutations in cytochrome b, none affect amino acids known to be determinants of atovaquone sensitivity and atovaquone is still able to inhibit electron transport in the Tgmsh1 mutants. Furthermore, culture of Tgmsh1 mutant in the presence atovaquone leads to parasites with enhanced atovaquone resistance and complete shutdown of respiration. Thus, parasites lacking TgMSH1 overcome the disruption of mitochondrial DNA by adapting their physiology allowing them to forgo the need for oxidative phosphorylation. Consistent with this idea, the Tgmsh1 mutant is resistant to mitochondrial inhibitors with diverse targets and exhibits reduced ability to grow in the absence of glucose. This work shows TgMSH1 as critical for the maintenance and fidelity of the mitochondrial DNA in Toxoplasma

  2. Interaction of pathogens with host cholesterol metabolism.

    Science.gov (United States)

    Sviridov, Dmitri; Bukrinsky, Michael

    2014-10-01

    Pathogens of different taxa, from prions to protozoa, target cellular cholesterol metabolism to advance their own development and to impair host immune responses, but also causing metabolic complications, for example, atherosclerosis. This review describes recent findings of how pathogens do it. A common theme in interaction between pathogens and host cholesterol metabolism is pathogens targeting lipid rafts of the host plasma membrane. Many intracellular pathogens use rafts as an entry gate, taking advantage of the endocytic machinery and high abundance of outward-looking molecules that can be used as receptors. At the same time, disruption of the rafts' functional capacity, achieved by the pathogens through a number of various means, impairs the ability of the host to generate immune response, thus helping pathogen to thrive. Pathogens cannot synthesize cholesterol, and salvaging host cholesterol helps pathogens build advanced cholesterol-containing membranes and assembly platforms. Impact on cholesterol metabolism is not limited to the infected cells; proteins and microRNAs secreted by infected cells affect lipid metabolism systemically. Given an essential role that host cholesterol metabolism plays in pathogen development, targeting this interaction may be a viable strategy to fight infections, as well as metabolic complications of the infections.

  3. [Seroprevalance Differences of Toxoplasma Between Syrian Refugees Pregnants and Indigenous Turkish Pregnants in Kahramanmaraş].

    Science.gov (United States)

    Bakacak, Murat; Serin, Salih; Aral, Murat; Ercan, Önder; Köstü, Bülent; Kireçci, Ahmet; Bostancı, Mehmet Sühha; Bakacak, Zeyneb

    2015-06-01

    In this study, we aimed to compare the Syrian refugees and resident Turkish pregnant population in terms of Toxoplasma seroprevalence. Data acquired from Kahramanmaraş Necip Fazıl City Hospital Department of Obstetrics and Gynecology between 2012 and 2013 were analyzed retrospectively. Results of 7201 Toxoplasma IgM tests and 4113 Toxoplasma IgG tests were evaluated. For 2012 and 2013 Toxoplasma IgM seropositivity was found in Syrian refugees 4.76% and 4.84% respectively in our study. In the same population Toxoplasma IgG seropositivity rates were 80% and 62.6%, respectively. Toxoplasma IgM seropositivity rates for the native peoples in Turkey in 2012 and 2013 was 1.96% and 2.34%, while in the same population Toxoplasma IgG seropositivity was detected 49.7% and 45.7% respectively. Toxoplasma IgM seropositivity was statistically higher in Syrian refugees for each year (p Syrian refugees was statistically higher (p Syrian refugees living in the region of Kahramanmaraş were statistically higher than the rates of local inhabitants, we consider that this condition should be taken into account in the follow-ups of Syrian pregnant refugees outnumbering in Kahramanmaraş and its vicinity.

  4. Toxoplasma gondii IgG antibodies in HIV/AIDS patients attending ...

    African Journals Online (AJOL)

    Background: Toxoplasmosis is caused by Toxoplasma gondii, a parasite that gradually evolved to be the most opportunistic parasite that complicates the course of HIV/AIDS in developing countries. Aim: This study was undertaken to investigate the presence of Toxoplasma gondii IgG antibodies in HIVinfected patients ...

  5. Toxoplasma gondii: Biochemical and biophysical characterization of recombinant soluble dense granule proteins GRA2 and GRA6

    International Nuclear Information System (INIS)

    Bittame, Amina; Effantin, Grégory; Pètre, Graciane; Ruffiot, Pauline; Travier, Laetitia; Schoehn, Guy; Weissenhorn, Winfried; Cesbron-Delauw, Marie-France; Gagnon, Jean; Mercier, Corinne

    2015-01-01

    The most prominent structural feature of the parasitophorous vacuole (PV) in which the intracellular parasite Toxoplasma gondii proliferates is a membranous nanotubular network (MNN), which interconnects the parasites and the PV membrane. The MNN function remains unclear. The GRA2 and GRA6 proteins secreted from the parasite dense granules into the PV have been implicated in the MNN biogenesis. Amphipathic alpha-helices (AAHs) predicted in GRA2 and an alpha-helical hydrophobic domain predicted in GRA6 have been proposed to be responsible for their membrane association, thereby potentially molding the MMN in its structure. Here we report an analysis of the recombinant proteins (expressed in detergent-free conditions) by circular dichroism, which showed that full length GRA2 displays an alpha-helical secondary structure while recombinant GRA6 and GRA2 truncated of its AAHs are mainly random coiled. Dynamic light scattering and transmission electron microscopy showed that recombinant GRA6 and truncated GRA2 constitute a homogenous population of small particles (6–8 nm in diameter) while recombinant GRA2 corresponds to 2 populations of particles (∼8–15 nm and up to 40 nm in diameter, respectively). The unusual properties of GRA2 due to its AAHs are discussed. - Highlights: • Toxoplasma gondii: soluble GRA2 forms 2 populations of particles. • T. gondii: the dense granule protein GRA2 folds intrinsically as an alpha-helix. • T. gondii: monomeric soluble GRA6 forms particles of 6–8 nm in diameter. • T. gondii: monomeric soluble GRA6 is random coiled. • Unusual biophysical properties of the dense granule protein GRA2 from T. gondii

  6. Toxoplasma gondii: Biochemical and biophysical characterization of recombinant soluble dense granule proteins GRA2 and GRA6

    Energy Technology Data Exchange (ETDEWEB)

    Bittame, Amina [CNRS, UMR 5163, 38042 Grenoble (France); Université Grenoble Alpes, 38042 Grenoble (France); Effantin, Grégory [Université Grenoble Alpes, Institut de Biologie Structurale (IBS), 38044 Grenoble (France); CNRS, IBS, 38044 Grenoble (France); CEA, IBS, 38044 Grenoble (France); Unit for Virus Host-Cell Interactions (UVHCI), UMI 3265 (UJF-EMBL-CNRS), 38027 Grenoble (France); Pètre, Graciane; Ruffiot, Pauline; Travier, Laetitia [CNRS, UMR 5163, 38042 Grenoble (France); Université Grenoble Alpes, 38042 Grenoble (France); Schoehn, Guy; Weissenhorn, Winfried [Université Grenoble Alpes, Institut de Biologie Structurale (IBS), 38044 Grenoble (France); CNRS, IBS, 38044 Grenoble (France); CEA, IBS, 38044 Grenoble (France); Unit for Virus Host-Cell Interactions (UVHCI), UMI 3265 (UJF-EMBL-CNRS), 38027 Grenoble (France); Cesbron-Delauw, Marie-France; Gagnon, Jean [CNRS, UMR 5163, 38042 Grenoble (France); Université Grenoble Alpes, 38042 Grenoble (France); Mercier, Corinne, E-mail: corinne.mercier@ujf-grenoble.fr [CNRS, UMR 5163, 38042 Grenoble (France); Université Grenoble Alpes, 38042 Grenoble (France)

    2015-03-27

    The most prominent structural feature of the parasitophorous vacuole (PV) in which the intracellular parasite Toxoplasma gondii proliferates is a membranous nanotubular network (MNN), which interconnects the parasites and the PV membrane. The MNN function remains unclear. The GRA2 and GRA6 proteins secreted from the parasite dense granules into the PV have been implicated in the MNN biogenesis. Amphipathic alpha-helices (AAHs) predicted in GRA2 and an alpha-helical hydrophobic domain predicted in GRA6 have been proposed to be responsible for their membrane association, thereby potentially molding the MMN in its structure. Here we report an analysis of the recombinant proteins (expressed in detergent-free conditions) by circular dichroism, which showed that full length GRA2 displays an alpha-helical secondary structure while recombinant GRA6 and GRA2 truncated of its AAHs are mainly random coiled. Dynamic light scattering and transmission electron microscopy showed that recombinant GRA6 and truncated GRA2 constitute a homogenous population of small particles (6–8 nm in diameter) while recombinant GRA2 corresponds to 2 populations of particles (∼8–15 nm and up to 40 nm in diameter, respectively). The unusual properties of GRA2 due to its AAHs are discussed. - Highlights: • Toxoplasma gondii: soluble GRA2 forms 2 populations of particles. • T. gondii: the dense granule protein GRA2 folds intrinsically as an alpha-helix. • T. gondii: monomeric soluble GRA6 forms particles of 6–8 nm in diameter. • T. gondii: monomeric soluble GRA6 is random coiled. • Unusual biophysical properties of the dense granule protein GRA2 from T. gondii.

  7. Vaccination with a DNA vaccine encoding Toxoplasma gondii ROP54 induces protective immunity against toxoplasmosis in mice.

    Science.gov (United States)

    Yang, Wen-Bin; Zhou, Dong-Hui; Zou, Yang; Chen, Kai; Liu, Qing; Wang, Jin-Lei; Zhu, Xing-Quan; Zhao, Guang-Hui

    2017-12-01

    Toxoplasma gondii is an obligatory intracellular protozoan, which infects most of the warm-blooded animals, causing serious public health problems and enormous economic losses worldwide. The rhoptry effector protein 54 (ROP54) has been indicated as a virulence factor that promotes Toxoplasma infection by modulating GBP2 loading onto parasite-containing vacuoles, which can modulate some aspects of the host immune response. In order to evaluate the immuno-protective value of ROP54, we constructed a eukaryotic recombinant plasmid expressing T. gondii ROP54 and intramuscularly immunized Kunming mice with this recombinant plasmid against acute and chronic toxoplasmosis. All mice immunized with pVAX-ROP54 elicited a high level of specific antibody responses, a significant increase of lymphocyte proliferation, and a significant level of Th1-type cytokines (IFN-γ, IL-2 and IL-12p70), in addition to an increased production of Th2-type cytokines (IL-4 and IL-10). These results demonstrated that pVAX-ROP54 induced significant cellular and humoral (Th1/Th2) immune responses, which extended the survival time (13.0±1.15days for pVAX-ROP54 vs 6.7±0.48days for pVAX I, 6.8±0.42days for PBS and 6.5±0.53 for blank control) and significantly reduced cyst burden (35.9% for pVAX-ROP54, 1% for pVAX I and 2% for PBS, compared with blank control) of immunized mice. These results indicate that the recombinant ROP54 plasmid can provide partial protection and might be a potential vaccine candidate against acute and chronic toxoplasmosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  8. Screening of Toxoplasma gondii infection among childbearing age females and assessment of nurses' role in prevention and control of toxoplasmosis.

    Science.gov (United States)

    Saleh, Ahmed Megahed Ahmed; Ali, Hisham abd El-Raouf; Ahmed, Salwa Abdalla Mohamed; Hosny, Samah Mostafa; Morsy, Tosson A

    2014-08-01

    Toxoplasmosis, caused by Toxoplasma gondii is an obligate intracellular zoonotic protozoan parasite, with a worldwide distribution particularly in Arab countries including Egypt. The study evaluated toxoplasmosis infection among childbearing age Egyptian females and assessed the military nursing staff knowledge, attitude and compliance to toxoplasmosis prevention and control measures. The study was conductedin a general military hospital. CROSS-section descriptive research design was used to conduct this study. The subjects consisted of 14 young females (11 were in-patients undergoing gynecological treatment in a military hospital and 3 were staff nurses. On the other hand, 44 staff nurses were available for assessment who met the inclusion criteria. 4 tools were used for data collection: first consisted of self-administered questionnaires to assess nurses' socio-demographic data and knowledge, second rating scale to assess nurses' attitude towards toxoplasmosis infection and its prevention, third performance check list to measure nurses' compliance to infection control measures, and fourth measured the anti-Toxoplasma antibodies by commercial indirect hemagglutination test (IHAT). The results showed that almost half of the nurses had satisfactory levels of knowledge, attitude, and compliance to toxoplasmosis infection control measures. 22.2% of the pregnant women and 20% of non-pregnant ones showed antibodies against T. gondii. Thus health education about toxoplasmosis should be tailored to women whether married or single to help in avoiding the risk of infection. Frequent periodic IHAT should be done for people who continuously contact with cats. Adherence to strict infection prevention measures is a must to eliminate exposure to toxoplasmosis infection. Training intervention should be implemented to achieve successful improvement in knowledge, attitude, and compliance of toxoplasmosis control measures.

  9. Detection of Toxoplasma gondii in Diabetic Patients Using the Nested PCR Assay via RE and B1 Genes.

    Science.gov (United States)

    Mousavi, Mohammad; Saravani, Ramin; Jafari Modrek, Mohammad; Shahrakipour, Mahnaz; Sekandarpour, Sina

    2016-02-01

    Toxoplasma gondii is an obligate intracellular protozoan parasite that exists worldwide. Various techniques have been developed for T. gondii detection. The aim of this study was the detection of T. gondii in diabetic patients with RE and B1 genes and the comparison of these two genes for diagnosis using the nested-PCR assay method. DNA samples from 205 diabetic patients who had been referred to the diabetes center of Ali Asghar hospital in Zahedan, Iran, were collected and analyzed using the nested-PCR assay method. Toxoplasma antibody data gathered using the enzyme-linked immunosorbent assay (ELISA) method from a previous study was used to group patients. The data were analyzed using SPSS 18. The chi-square test was used for comparison. Of the diabetic patients selected, the following results were obtained: 53 (IgG+, IgM+); 20 (IgG-, IgM+); 72 (IgG+, IgM-); and 60 (IgG-, IgM-). The nested-PCR detected the following: in the acute group, 21/53 (39.63%), 30/53 (56.60%) (IgM+, IgG+); in the chronic group, 40/72 (55.56%), 51/72 (70.83%), (IgG+, IgM-); in the false positive group, 18/20 (90%), 17/20 (85%) (IgM+, IgG-); and sero-negative samples of 38/60 (63.33%) and 60/ 41 (77.35%) for RE and B1 genes, respectively. The prevalence of toxoplasmosis showed positive in patients with diabetes in the B1 gene 139 (67.8%) and RE gene 117 (57.1%). Our study demonstrated that the B1 gene, more so than the RE gene, showed positive samples and can be used to detect toxoplasmosis, although the B1 gene, in comparison to the RE gene, did not show any superiority of molecular diagnosing capability. Results also showed that toxoplasma molecular detection methods can be used instead of routine serological detection methods in a clinical laboratory testing.

  10. Antibody- and TRIM21-dependent intracellular restriction of Salmonella enterica.

    Science.gov (United States)

    Rakebrandt, Nikolas; Lentes, Sabine; Neumann, Heinz; James, Leo C; Neumann-Staubitz, Petra

    2014-11-01

    TRIM21 ('tripartite motif-containing protein 21', Ro52) is a ubiquitously expressed cytosolic Fc receptor, which has a potent role in protective immunity against nonenveloped viruses. TRIM21 mediates intracellular neutralisation of antibody-coated viruses, a process called ADIN (antibody-dependent intracellular neutralisation). Our results reveal a similar mechanism to fight bacterial infections. TRIM21 is recruited to the intracellular pathogen Salmonella enterica in epithelial cells early in infection. TRIM21 does not bind directly to S. enterica, but to antibodies opsonising it. Most importantly, bacterial restriction is dependent on TRIM21 as well as on the opsonisation state of the bacteria. Finally, Salmonella and TRIM21 colocalise with the autophagosomal marker LC3, and intracellular defence is enhanced in starved cells suggesting an involvement of the autophagocytic pathway. Our data extend the protective role of TRIM21 from viruses to bacteria and thereby strengthening the general role of ADIN in cellular immunity. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  11. Organizational changes of the daughter basal complex during the parasite replication of Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Ke Hu

    2008-01-01

    Full Text Available The apicomplexans are a large group of parasitic protozoa, many of which are important human and animal pathogens, including Plasmodium falciparum and Toxoplasma gondii. These parasites cause disease only when they replicate, and their replication is critically dependent on the proper assembly of the parasite cytoskeletons during cell division. In addition to their importance in pathogenesis, the apicomplexan parasite cytoskeletons are spectacular structures. Therefore, understanding the cytoskeletal biogenesis of these parasites is important not only for parasitology but also of general interest to broader cell biology. Previously, we found that the basal end of T. gondii contains a novel cytoskeletal assembly, the basal complex, a cytoskeletal compartment constructed in concert with the daughter cortical cytoskeleton during cell division. This study focuses on key events during the biogenesis of the basal complex using high resolution light microscopy, and reveals that daughter basal complexes are established around the duplicated centrioles independently of the structural integrity of the daughter cortical cytoskeleton, and that they are dynamic "caps" at the growing ends of the daughters. Compartmentation and polarization of the basal complex is first revealed at a late stage of cell division upon the recruitment of an EF-hand containing calcium binding protein, TgCentrin2. This correlates with the constriction of the basal complex, a process that can be artificially induced by increasing cellular calcium concentration. The basal complex is therefore likely to be a new kind of centrin-based contractile apparatus.

  12. "Latent" infection with Toxoplasma gondii: association with trait aggression and impulsivity in healthy adults.

    Science.gov (United States)

    Cook, Thomas B; Brenner, Lisa A; Cloninger, C Robert; Langenberg, Patricia; Igbide, Ajirioghene; Giegling, Ina; Hartmann, Annette M; Konte, Bettina; Friedl, Marion; Brundin, Lena; Groer, Maureen W; Can, Adem; Rujescu, Dan; Postolache, Teodor T

    2015-01-01

    Latent chronic infection with Toxoplasma gondii (T. gondii), a common neurotropic pathogen, has been previously linked with suicidal self-directed violence (SSDV). We sought to determine if latent infection with T. gondii is associated with trait aggression and impulsivity, intermediate phenotypes for suicidal behavior, in psychiatrically healthy adults. Traits of aggression and impulsivity were analyzed in relationship to IgG antibody seropositivity for T. gondii and two other latent neurotropic infections, herpes simplex virus 1 (HSV1) and cytomegalovirus (CMV). One thousand community-residing adults residing in the Munich metropolitan area with no Axis I or II conditions by SCID for DSM-IV (510 men, 490 women, mean age 53.6 ± 15.8, range 20-74). Plasma samples were tested for IgG antibodies to T. gondii, HSV-1 and CMV by ELISA. Self-reported ratings of trait aggression scores (Questionnaire for Measuring Factors of Aggression [FAF]) and trait impulsivity (Sensation-Seeking Scale-V [SSS-V]) were analyzed using linear multivariate methods. T. gondii IgG seropositivity was significantly associated with higher trait reactive aggression scores among women (p impulsive sensation-seeking (SSS-V Disinhibition) among younger men (p impulsivity, personality traits considered as endophenotypes for SSDV, are associated with latent T. gondii infection in a gender and age-specific manner, and could be further investigated as prognostic and treatment targets in T. gondii-positive individuals at risk for SSDV. Published by Elsevier Ltd.

  13. Atypical Toxoplasma gondii genotype in feral cats from the Fernando de Noronha Island, northeastern Brazil.

    Science.gov (United States)

    Melo, R P B; Almeida, J C; Lima, D C V; Pedrosa, C M; Magalhães, F J R; Alcântara, A M; Barros, L D; Vieira, R F C; Garcia, J L; Mota, R A

    2016-07-15

    Toxoplasma gondii isolates from Brazil have a different phenotypic and genotypic pattern, with predominance of virulent isolates and recombinant genotypes, compared to the North Hemisphere. Considering that a new T. gondii genotype, non-pathogenic to mice, was previously identified from free-range chickens from the Fernando de Noronha Island, Brazil, this study aimed to identify genotypes of this parasite in tissue samples of feral cats (Felis catus) from this Brazilian Island. Anti-T. gondii IgG antibodies were detected in 18/31 (58%) feral cats. Two non-virulent T. gondii isolates were obtained by mouse bioassay. Genotyping was performed by PCR-RFLP using 10 genetic markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, PK1, L358 and Apico) and an atypical strain of T. gondii (ToxoDB #146) was identified. This is the first report of this genotype in feral cats. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. An emerging cyberinfrastructure for biodefense pathogen and pathogen-host data.

    Science.gov (United States)

    Zhang, C; Crasta, O; Cammer, S; Will, R; Kenyon, R; Sullivan, D; Yu, Q; Sun, W; Jha, R; Liu, D; Xue, T; Zhang, Y; Moore, M; McGarvey, P; Huang, H; Chen, Y; Zhang, J; Mazumder, R; Wu, C; Sobral, B

    2008-01-01

    The NIAID-funded Biodefense Proteomics Resource Center (RC) provides storage, dissemination, visualization and analysis capabilities for the experimental data deposited by seven Proteomics Research Centers (PRCs). The data and its publication is to support researchers working to discover candidates for the next generation of vaccines, therapeutics and diagnostics against NIAID's Category A, B and C priority pathogens. The data includes transcriptional profiles, protein profiles, protein structural data and host-pathogen protein interactions, in the context of the pathogen life cycle in vivo and in vitro. The database has stored and supported host or pathogen data derived from Bacillus, Brucella, Cryptosporidium, Salmonella, SARS, Toxoplasma, Vibrio and Yersinia, human tissue libraries, and mouse macrophages. These publicly available data cover diverse data types such as mass spectrometry, yeast two-hybrid (Y2H), gene expression profiles, X-ray and NMR determined protein structures and protein expression clones. The growing database covers over 23 000 unique genes/proteins from different experiments and organisms. All of the genes/proteins are annotated and integrated across experiments using UniProt Knowledgebase (UniProtKB) accession numbers. The web-interface for the database enables searching, querying and downloading at the level of experiment, group and individual gene(s)/protein(s) via UniProtKB accession numbers or protein function keywords. The system is accessible at http://www.proteomicsresource.org/.

  15. Molecular and serological prevalence of Toxoplasma gondii and Anaplasma spp. infection in goats from Chongqing Municipality, China

    Directory of Open Access Journals (Sweden)

    Zhou Zuoyong

    2018-01-01

    Full Text Available Toxoplasmosis and anaplasmosis are severe zoonotic diseases, the former caused by Toxoplasma gondii and the latter by Anaplasma spp. In the present study, 332 goat blood samples were randomly collected from Chongqing Municipality, China to screen for T. gondii and Anaplasma spp. We used a polymerase chain reaction (PCR to detect DNA, and enzyme-linked immunosorbent assay (ELISA to test for T. gondii antibodies. The prevalence of T. gondii and Anaplasma spp. was 38% and 35% respectively by PCR, and 42% for T. gondii antibodies by ELISA. The co-infection rate by T. gondii and Anaplasma was 13%, where the two predominant pathogens co-infecting were Anaplasma phagocytophilum + A. bovis (10%, followed by T. gondii + A. phagocytophilum (9.64%. While co-infection by three pathogens varied ranging from 1.81% to 5.72%, less than 1% of goats were found to be positive for four pathogens. This is the first investigation of T. gondii and Anaplasma spp. infection in goats from Chongqing.

  16. Metabolism of the vacuolar pathogen Legionella and implications for virulence.

    Science.gov (United States)

    Manske, Christian; Hilbi, Hubert

    2014-01-01

    Legionella pneumophila is a ubiquitous environmental bacterium that thrives in fresh water habitats, either as planktonic form or as part of biofilms. The bacteria also grow intracellularly in free-living protozoa as well as in mammalian alveolar macrophages, thus triggering a potentially fatal pneumonia called "Legionnaires' disease." To establish its intracellular niche termed the "Legionella-containing vacuole" (LCV), L. pneumophila employs a type IV secretion system and translocates ~300 different "effector" proteins into host cells. The pathogen switches between two distinct forms to grow in its extra- or intracellular niches: transmissive bacteria are virulent for phagocytes, and replicative bacteria multiply within their hosts. The switch between these forms is regulated by different metabolic cues that signal conditions favorable for replication or transmission, respectively, causing a tight link between metabolism and virulence of the bacteria. Amino acids represent the prime carbon and energy source of extra- or intracellularly growing L. pneumophila. Yet, the genome sequences of several Legionella spp. as well as transcriptome and proteome data and metabolism studies indicate that the bacteria possess broad catabolic capacities and also utilize carbohydrates such as glucose. Accordingly, L. pneumophila mutant strains lacking catabolic genes show intracellular growth defects, and thus, intracellular metabolism and virulence of the pathogen are intimately connected. In this review we will summarize recent findings on the extra- and intracellular metabolism of L. pneumophila using genetic, biochemical and cellular microbial approaches. Recent progress in this field sheds light on the complex interplay between metabolism, differentiation and virulence of the pathogen.

  17. Detection and quantification of intracellular bacterial colonies by automated, high-throughput microscopy.

    Science.gov (United States)

    Ernstsen, Christina L; Login, Frédéric H; Jensen, Helene H; Nørregaard, Rikke; Møller-Jensen, Jakob; Nejsum, Lene N

    2017-08-01

    To target bacterial pathogens that invade and proliferate inside host cells, it is necessary to design intervention strategies directed against bacterial attachment, cellular invasion and intracellular proliferation. We present an automated microscopy-based, fast, high-throughput method for analyzing size and number of intracellular bacterial colonies in infected tissue culture cells. Cells are seeded in 48-well plates and infected with a GFP-expressing bacterial pathogen. Following gentamicin treatment to remove extracellular pathogens, cells are fixed and cell nuclei stained. This is followed by automated microscopy and subsequent semi-automated spot detection to determine the number of intracellular bacterial colonies, their size distribution, and the average number per host cell. Multiple 48-well plates can be processed sequentially and the procedure can be completed in one working day. As a model we quantified intracellular bacterial colonies formed by uropathogenic Escherichia coli (UPEC) during infection of human kidney cells (HKC-8). Urinary tract infections caused by UPEC are among the most common bacterial infectious diseases in humans. UPEC can colonize tissues of the urinary tract and is responsible for acute, chronic, and recurrent infections. In the bladder, UPEC can form intracellular quiescent reservoirs, thought to be responsible for recurrent infections. In the kidney, UPEC can colonize renal epithelial cells and pass to the blood stream, either via epithelial cell disruption or transcellular passage, to cause sepsis. Intracellular colonies are known to be clonal, originating from single invading UPEC. In our experimental setup, we found UPEC CFT073 intracellular bacterial colonies to be heterogeneous in size and present in nearly one third of the HKC-8 cells. This high-throughput experimental format substantially reduces experimental time and enables fast screening of the intracellular bacterial load and cellular distribution of multiple

  18. Stochastic models of intracellular transport

    KAUST Repository

    Bressloff, Paul C.

    2013-01-09

    The interior of a living cell is a crowded, heterogenuous, fluctuating environment. Hence, a major challenge in modeling intracellular transport is to analyze stochastic processes within complex environments. Broadly speaking, there are two basic mechanisms for intracellular transport: passive diffusion and motor-driven active transport. Diffusive transport can be formulated in terms of the motion of an overdamped Brownian particle. On the other hand, active transport requires chemical energy, usually in the form of adenosine triphosphate hydrolysis, and can be direction specific, allowing biomolecules to be transported long distances; this is particularly important in neurons due to their complex geometry. In this review a wide range of analytical methods and models of intracellular transport is presented. In the case of diffusive transport, narrow escape problems, diffusion to a small target, confined and single-file diffusion, homogenization theory, and fractional diffusion are considered. In the case of active transport, Brownian ratchets, random walk models, exclusion processes, random intermittent search processes, quasi-steady-state reduction methods, and mean-field approximations are considered. Applications include receptor trafficking, axonal transport, membrane diffusion, nuclear transport, protein-DNA interactions, virus trafficking, and the self-organization of subcellular structures. © 2013 American Physical Society.

  19. Iron in intracellular infection: to provide or to deprive?

    Directory of Open Access Journals (Sweden)

    Sandro eSilva-Gomes

    2013-12-01

    Full Text Available Due to their chemical versatility, transition metals were incorporated as cofactors for several basic metabolic pathways in living organisms. This same characteristic makes them potentially harmful, since they can be engaged in deleterious reactions like Fenton chemistry. As such, organisms have evolved highly specialized mechanisms to supply their own metal needs while keeping their toxic potential in check.This dual character comes into play in host-pathogen interactions, given that the host can either deprive the pathogen of these key nutrients or exploit them to induce toxicity towards the invading agent. Iron stands as the prototypic example of how a metal can be used to limit the growth of pathogens by nutrient deprivation, a mechanism widely studied in Mycobacterium infections. However, the host can also take advantage of iron-induced toxicity to control pathogen proliferation, as observed in infections caused by Leishmania. Whether we may harness either of the two pathways for therapeutical purposes is still ill-defined.In this review, we discuss how modulation of the host iron availability impacts the course of infections, focusing on those caused by two relevant intracellular pathogens, Mycobacterium and Leishmania.

  20. Seroprevalence of Toxoplasma gondii infection in goats from the south-west region of Poland and the detection of T. gondii DNA in goat milk.

    Science.gov (United States)

    Sroka, Jacek; Kusyk, Pawel; Bilska-Zajac, Ewa; Karamon, Jacek; Dutkiewicz, Jacek; Wojcik-Fatla, Angelina; Zajac, Violetta; Stojecki, Krzysztof; Rozycki, Miroslaw; Cencek, Tomasz

    2017-07-11

    Toxoplasma gondii (Nicolle et Manceaux, 1908) is an obligatory intracellular protozoan parasite prevalent in animals and humans worldwide having medical and veterinary importance on account of causing abortion or congenital disease in intermediate hosts, including man. Since T. gondii has already been identified in the milk of goats, Capra aegagrus hircus (Linnaeus), the possibility of acquiring infection by ingesting unpasteurised goat milk should be taken into consideration. Thus, the aim of the present study was to determine the presence of T. gondii DNA in goat milk. First, 73 goats (females) from 36 farms located in Poland were examined serologically by direct agglutination test (DAT) to estimate the T. gondii serological status. Milk samples from 60 selected lactating females were examined for the presence of T. gondii DNA by Real time PCR and nested PCR (B1 gene). To estimate the clonal type of detected T. gondii, multiplex PCR was performed using 6 markers. In DAT, positive results were found in 70% of 73 goats. Among examined 60 milk samples, 65% were positive in Real time PCR and 43% in nested PCR. It is noteworthy that 11 samples positive in PCR were collected from seronegative goats. The multilocus PCR analysis mostly revealed the occurrence of genotype III, which is relatively rare in Europe. The recorded high prevalence of anti-Toxoplasma antibodies in tested goats (70%), associated with a high prevalence of T. gondii DNA in goat milk samples (65%), indicates a potential risk of the parasite transmission through goat milk ingestion.

  1. Characterization of Leptin Intracellular Trafficking

    Directory of Open Access Journals (Sweden)

    E Walum

    2009-12-01

    Full Text Available Leptin is produced by adipose tissue, and its concentration in plasma is related to the amount of fat in the body. The leptin receptor (OBR is a member of the class I cytokine receptor family and several different isoforms, produced by alternative mRNA splicing are found in many tissues, including the hypothalamus. The two predominant isoforms includes a long form (OBRl with an intracellular domain of 303 amino acids and a shorter form (OBRs with an intracellular domain of 34 amino acids. Since OBRl is mainly expressed in the hypotalamus, it has been suggested to be the main signalling form. The peripheral production of leptin by adipocyte tissue and its effects as a signal of satiety in the central nervous system imply that leptin gains access to regions of the brain regulating in energy balance by crossing the blood-brain barrier. In an attempt to characterize the intracellular transport of leptin, we have followed binding internalization and degradation of leptin in HEK293 cells. We have also monitored the intracellular transport pathway of fluorescent conjugated leptin in HEK293 cells. Phenylarsine oxide, a general inhibitor of endocytosis, as well as incubation at mild hypertonic conditions, prevented the uptake of leptin, confirming a receptor-mediated internalization process. When internalized, 125I-leptin was rapidly accumulated inside the cells and reached a maximum after 10 min. After 70 minutes about 40-50% of total counts in each time point were found in the medium as TCA-soluble material. Leptin sorting, at the level of early endosomes, did not seem to involve recycling endosomes, since FITC-leptin was sorted from Cy3- transferrin containing compartments at 37°C. At 45 minutes of continuos internalization, FITC-leptin appeared mainly accumulated in late endocytic structures colocalizing with internalized rhodamine coupled epidermial growth factor (EGF and the lysosomal marker protein lamp-1. The transport of leptin was also shown

  2. The Role of Pathogenic Autoantibodies in Autoimmunity

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    Merrill J. Rowley

    2015-11-01

    Full Text Available The serological presence of autoantibodies is diagnostic of autoimmunity, and these autoantibodies may be present for many years before the presentation of autoimmune disease (AID. Although a pathogenic role has been demonstrated for various autoantibodies reactive with cell surface and extracellular autoantigens, studies using monoclonal antibodies (mAb show not all antibodies in the polyclonal response are pathogenic. Differences depend on Fab-mediated diversity in epitope specificity, Fc-mediated effects based on immunoglobulin (Ig class and subclass, activation of complement, and the milieu in which the reaction occurs. These autoantibodies often occur in organ-specific AID and this review illustrates their pathogenic and highly specific effects. The role of autoantibodies associated with intracellular antigens is less clear. In vitro they may inhibit or adversely affect well-defined intracellular biochemical pathways, yet, in vivo they are separated from their autoantigens by multiple cellular barriers. Recent evidence that Ig can traverse cell membranes, interact with intracellular proteins, and induce apoptosis has provided new evidence for a pathogenic role for such autoantibodies. An understanding of how autoantibodies behave in the polyclonal response and their role in pathogenesis of AID may help identify populations of culprit B-cells and selection of treatments that suppress or eliminate them.

  3. Susceptibility of pregnant women to toxoplasma infection--potential benefits for newborn screening.

    LENUS (Irish Health Repository)

    Ferguson, W

    2008-08-20

    Congenital toxoplasmosis (CT) arises as a result of new acquisition of Toxoplasma infection by a susceptible woman during pregnancy. Early detection of CT through neonatal screening programmes could optimize management and improve infant outcome. This study sought to estimate the prevalence of Toxoplasma susceptibility in pregnant women. As detection of Toxoplasma antibodies in neonatal blood reflects maternal exposure history, maternal antibody seroprevalence was determined using anonymized residual blood from newborn screening cards. A total of 20,252 cards were tested in 1 year. 4,991 (24.6%) cards tested positive for Toxoplasma antibody. Results were stratified by county. Toxoplasma antibody seroprevalence rates of 25% indicated that Toxoplasma infection is common in Ireland and that up to 75% of women remain susceptible to primary infection during pregnancy. This study aimed to a) determine the seroprevalence of Toxoplasma antibody in pregnant women, and hence b) estimate the risk for acquisition of primary toxoplasmosis in pregnancy in order to support an application to fund a pilot newborn screening programme.

  4. Toxoplasma gondii antibodies in the white stork Ciconia ciconia.

    Science.gov (United States)

    Andrzejewska, Izabela; Tryjanowski, Piotr; Zduniak, Piotr; Dolata, Pawel T; Ptaszyk, Jerzy; Cwiertnia, Piotr

    2004-01-01

    The prevalence of Toxoplasma gondii in chicks of wild birds and captive individuals was studied in the Poznań environs and in the Poznań Zoological Garden in the years 2002-2003. Bird blood was tested for T. gondii antibodies by an indirect fluorescent antibody test. T. gondii antibodies were detected from 5.8% of 205 analysed white stork chicks and 13.6% of 44 analysed adult storks in the zoo. Because toxoplasmosis is one of the more common parasitic zoonoses worldwide, we briefly discuss the potential epidemiological importance of stork toxoplasmosis to humans.

  5. Intracellularly Induced Cyclophilins Play an Important Role in Stress Adaptation and Virulence of Brucella abortus

    Science.gov (United States)

    García Fernández, Lucía; DelVecchio, Vito G.; Briones, Gabriel

    2013-01-01

    Brucella is an intracellular bacterial pathogen that causes the worldwide zoonotic disease brucellosis. Brucella virulence relies on its ability to transition to an intracellular lifestyle within host cells. Thus, this pathogen must sense its intracellular localization and then reprogram gene expression for survival within the host cell. A comparative proteomic investigation was performed to identify differentially expressed proteins potentially relevant for Brucella intracellular adaptation. Two proteins identified as cyclophilins (CypA and CypB) were overexpressed in the intracellular environment of the host cell in comparison to laboratory-grown Brucella. To define the potential role of cyclophilins in Brucella virulence, a double-deletion mutant was constructed and its resulting phenotype was characterized. The Brucella abortus ΔcypAB mutant displayed increased sensitivity to environmental stressors, such as oxidative stress, pH, and detergents. In addition, the B. abortus ΔcypAB mutant strain had a reduced growth rate at lower temperature, a phenotype associated with defective expression of cyclophilins in other microorganisms. The B. abortus ΔcypAB mutant also displays reduced virulence in BALB/c mice and defective intracellular survival in HeLa cells. These findings suggest that cyclophilins are important for Brucella virulence and survival in the host cells. PMID:23230297

  6. Seroprevalence of Anti-Toxoplasma gondii Antibodies Among Lebanese Pregnant Women.

    Science.gov (United States)

    Nahouli, Hasan; El Arnaout, Nour; Chalhoub, Elias; Anastadiadis, Elie; El Hajj, Hiba

    2017-12-01

    Toxoplasma gondii, the causative agent of toxoplasmosis, is a zoonotic obligate intracellular protozoan parasite responsible for the infection of almost one-third of the world's population. T. gondii is particularly threatening for primo-infected pregnant women and may lead, following vertical transplacental transmission, to spontaneous abortion, miscarriage, or severe manifestations in the newborn. The aim of this study was to provide an updated estimate of the seroprevalence of anti-T. gondii antibodies among a group of Lebanese pregnant women and its seroconversion rate. This is a retrospective cohort study, in which medical records of 11,000 pregnant women were screened. These women visited a private Obstetrics and Gynecology clinic located in Beirut, the capital of Lebanon, during the period of January 1994 till September 2015. Serological results of anti-T. gondii immunoglobulin G (IgG) and immunoglobulin M (IgM) results of 2456 Lebanese pregnant women who fulfilled the inclusion criteria were included in the analysis. Seropositivity and seroconversion rates for women with repeated tests were reported according to age and area of residence. The overall anti-T. gondii IgG and IgM seropositivity among 2456 Lebanese pregnant women was 82.6% and 1.8% respectively. The highest IgG seropositivity is among the age group of 35-44 years (87.81%) and at the governorate of "Mount Lebanon" (82.95%). Sixty-four seroconversions were detected and two abortions due to T. gondii infection during pregnancy were recorded. The seroprevalence of anti-T. gondii IgG among the screened pregnant women in Lebanon is the highest in the Arab region. These results highlight the importance of running a national sample survey to estimate the real potential burden of this infection and its impact on maternal and fetal health.

  7. First report of Toxoplasma gondii seroprevalence in peafowls in Yunnan Province, Southwestern China

    Directory of Open Access Journals (Sweden)

    Tian Yi-Ming

    2012-09-01

    Full Text Available Abstract Background Toxoplasma gondii is an intracellular protozoan parasite infecting almost all warm-blooded animals, including birds, with a worldwide distribution. Surveys of T. gondii infection in wild birds have been reported extensively in the world, but little is known of T. gondii infection in peafowls worldwide. This study was performed to determine the seroprevalence of T. gondii infection in peafowls in Yunnan Province, southwestern China. Methods Sera from 277 peafowls, including 272 blue peafowls (Pavo cristatus and 5 green peafowls (Pavo muticus originated from two geographic areas in Yunnan Province were assayed for T. gondii antibodies using the modified agglutination test (MAT. Results Specific T. gondii antibodies were detected in 35 of 277 (12.64% peafowls (MAT titer ≥ 1:5. Seropositive birds were found in both species, 33 in 272 blue peafowls and 2 in 5 green peafowls. There was no significant difference in T. gondii seroprevalence between the adolescent birds (6.74% and the adult birds (6.67% (P > 0.05. The geographical origins of peafowls was found to be highly associated with T. gondii infection in the present study, a statistically significant difference in T. gondii seropositivity was observed between peafowls from Kunming (31.08% and those from Xishuangbanna Dai Autonomous Prefecture (5.91% (OR = 10.956, 95% CI = 1.632-73.545, P = 0.014. Statistical analyses showed that there were no significant interactions between ages and geographical origins of peafowls (P > 0.05. Conclusions The results of the present survey indicated that infection of peafowls with T. gondii is widespread in Yunnan Province, which has significant public health concerns and implications for prevention and control of toxoplamosis in this province. To our knowledge, this is the first seroprevalence report of T. gondii infection in China’s southwestern Yunnan Province.

  8. First report of Toxoplasma gondii seroprevalence in peafowls in Yunnan Province, Southwestern China.

    Science.gov (United States)

    Tian, Yi-Ming; Dai, Fei-Yan; Huang, Si-Yang; Deng, Zu-Hong; Duan, Gang; Zhou, Dong-Hui; Yang, Jian-Fa; Weng, Ya-Biao; Zhu, Xing-Quan; Zou, Feng-Cai

    2012-09-19

    Toxoplasma gondii is an intracellular protozoan parasite infecting almost all warm-blooded animals, including birds, with a worldwide distribution. Surveys of T. gondii infection in wild birds have been reported extensively in the world, but little is known of T. gondii infection in peafowls worldwide. This study was performed to determine the seroprevalence of T. gondii infection in peafowls in Yunnan Province, southwestern China. Sera from 277 peafowls, including 272 blue peafowls (Pavo cristatus) and 5 green peafowls (Pavo muticus) originated from two geographic areas in Yunnan Province were assayed for T. gondii antibodies using the modified agglutination test (MAT). Specific T. gondii antibodies were detected in 35 of 277 (12.64%) peafowls (MAT titer ≥ 1:5). Seropositive birds were found in both species, 33 in 272 blue peafowls and 2 in 5 green peafowls. There was no significant difference in T. gondii seroprevalence between the adolescent birds (6.74%) and the adult birds (6.67%) (P > 0.05). The geographical origins of peafowls was found to be highly associated with T. gondii infection in the present study, a statistically significant difference in T. gondii seropositivity was observed between peafowls from Kunming (31.08%) and those from Xishuangbanna Dai Autonomous Prefecture (5.91%) (OR = 10.956, 95% CI = 1.632-73.545, P = 0.014). Statistical analyses showed that there were no significant interactions between ages and geographical origins of peafowls (P > 0.05). The results of the present survey indicated that infection of peafowls with T. gondii is widespread in Yunnan Province, which has significant public health concerns and implications for prevention and control of toxoplamosis in this province. To our knowledge, this is the first seroprevalence report of T. gondii infection in China's southwestern Yunnan Province.

  9. Seropositivity and risk factors associated with Toxoplasma gondii infection in wild birds from Spain.

    Directory of Open Access Journals (Sweden)

    Oscar Cabezón

    Full Text Available Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n=610, Strigiformes (n=260, Ciconiiformes (n=156, Gruiformes (n=21, and other orders (n=32, from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1:25 were found in 282 (26.1%, IC(95%:23.5-28.7 of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus, short-toed snake-eagle (Circaetus gallicus, Bonelli's eagle (Aquila fasciata, golden eagle (Aquila chrysaetos, bearded vulture (Gypaetus barbatus, osprey (Pandion haliaetus, Montagu's harrier (Circus pygargus, Western marsh-harrier (Circus aeruginosus, peregrine falcon (Falco peregrinus, long-eared owl (Asio otus, common scops owl (Otus scops, Eurasian spoonbill (Platalea leucorodia, white stork (Ciconia ciconia, grey heron (Ardea cinerea, common moorhen (Gallinula chloropus; in the International Union for Conservation of Nature (IUCN "vulnerable" Spanish imperial eagle (Aquila adalberti, lesser kestrel (Falco naumanni and great bustard (Otis tarda; and in the IUCN "near threatened" red kite (Milvus milvus. The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo (68.1%, 98 of 144. The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild

  10. Detection and quantification of intracellular bacterial colonies by automated, high-throughput microscopy

    DEFF Research Database (Denmark)

    Ernstsen, Christina L; Login, Frédéric H; Jensen, Helene H

    2017-01-01

    To target bacterial pathogens that invade and proliferate inside host cells, it is necessary to design intervention strategies directed against bacterial attachment, cellular invasion and intracellular proliferation. We present an automated microscopy-based, fast, high-throughput method for analy...

  11. Electron Microscopy of Intracellular Protozoa

    Science.gov (United States)

    1988-12-20

    Classification) " ELECTRON MICROSCOPY OF INTRACELLULAR PROTOZOA 12. PERSONAL AUTHOR(S) Aikawa, Masamichi 13a. TYPE OF REPORT I13b. TIME COVERED 114...authors suggest that anti-CS protein antibody is important in reducing the prevalence of malaria with increasing age among persons in such areas and... Hygine 33, 220-226. 0Giudice, G.D., Engers, H.D., Tougne, C., Biro, S.S., Weiss, N., Verdini, A.S., Pessi, A., Degremont, A.A., Freyvogel, T.A., Lambert

  12. Economic Game Theory to Model the Attenuation of Virulence of an Obligate Intracellular Bacterium.

    Science.gov (United States)

    Tago, Damian; Meyer, Damien F

    2016-01-01

    Diseases induced by obligate intracellular pathogens have a large burden on global human and animal health. Understanding the factors involved in the virulence and fitness of these pathogens contributes to the development of control strategies against these diseases. Based on biological observations, a theoretical model using game theory is proposed to explain how obligate intracellular bacteria interact with their host. The equilibrium in such a game shows that the virulence and fitness of the bacterium is host-triggered and by changing the host's defense system to which the bacterium is confronted, an evolutionary process leads to an attenuated strain. Although, the attenuation procedure has already been conducted in practice in order to develop an attenuated vaccine (e.g., with Ehrlichia ruminantium), there was a lack of understanding of the theoretical basis behind this process. Our work provides a model to better comprehend the existence of different phenotypes and some underlying evolutionary mechanisms for the virulence of obligate intracellular bacteria.

  13. Antibody reaction of human anti-Toxoplasma gondii positive and negative sera with Neospora caninum antigens

    OpenAIRE

    Nam, Ho-Woo; Kang, Seung-Won; Choi, Won-Young

    1998-01-01

    Anti-Neospora caninum antibody was detected in anti-Toxoplasma gondii positive and negative human sera by ELISA, western blot and immunofluorescence assay (IFA). Twelve cases out of 172 (6.7%) Toxoplasma-positive sera cross-reacted with both T. gondii and N. caninum antigens, and one out of 110 Toxoplasma-negative sera reacted with N. caninum antigen by ELISA. By western blot, all 12 sera reacted with T. gondii antigens with various banding patterns but specifically at 30 kDa (SAG1) and 22 kD...

  14. Modulation of pathogen recognition by autophagy

    Directory of Open Access Journals (Sweden)

    Ji Eun eOh

    2012-03-01

    Full Text Available Autophagy is an ancient biological process for maintaining cellular homeostasis by degradation of long-lived cytosolic proteins and organelles. Recent studies demonstrated that autophagy is availed by immune cells to regulate innate immunity. On the one hand, cells exert direct effector function by degrading intracellular pathogens; on the other hand, autophagy modulates pathogen recognition and downstream signaling for innate immune responses. Pathogen recognition via pattern recognition receptors induces autophagy. The function of phagocytic cells is enhanced by recruitment of autophagy-related proteins. Moreover, autophagy acts as a delivery system for viral replication complexes to migrate to the endosomal compartments where virus sensing occurs. In another case, key molecules of the autophagic pathway have been found to negatively regulate immune signaling, thus preventing aberrant activation of cytokine production and consequent immune responses. In this review, we focus on the recent advances in the role of autophagy in pathogen recognition and modulation of innate immune responses.

  15. Promotion and Rescue of Intracellular Brucella neotomae Replication during Coinfection with Legionella pneumophila.

    Science.gov (United States)

    Kang, Yoon-Suk; Kirby, James E

    2017-05-01

    We established a new Brucella neotomae in vitro model system for study of type IV secretion system-dependent (T4SS) pathogenesis in the Brucella genus. Importantly, B. neotomae is a rodent pathogen, and unlike B. abortus , B. melitensis , and B. suis , B. neotomae has not been observed to infect humans. It therefore can be handled more facilely using biosafety level 2 practices. More particularly, using a series of novel fluorescent protein and lux operon reporter systems to differentially label pathogens and track intracellular replication, we confirmed T4SS-dependent intracellular growth of B. neotomae in macrophage cell lines. Furthermore, B. neotomae exhibited early endosomal (LAMP-1) and late endoplasmic reticulum (calreticulin)-associated phagosome maturation. These findings recapitulate prior observations for human-pathogenic Brucella spp. In addition, during coinfection experiments with Legionella pneumophila , we found that defective intracellular replication of a B. neotomae T4SS virB4 mutant was rescued and baseline levels of intracellular replication of wild-type B. neotomae were significantly stimulated by coinfection with wild-type but not T4SS mutant L. pneumophila Using confocal microscopy, it was determined that intracellular colocalization of B. neotomae and L. pneumophila was required for rescue and that colocalization came at a cost to L. pneumophila fitness. These findings were not completely expected based on known temporal and qualitative differences in the intracellular life cycles of these two pathogens. Taken together, we have developed a new system for studying in vitro Brucella pathogenesis and found a remarkable T4SS-dependent interplay between Brucella and Legionella during macrophage coinfection. Copyright © 2017 American Society for Microbiology.

  16. Toxoplasma gondii and schizophrenia: a review of published RCTs.

    Science.gov (United States)

    Chorlton, Sam D

    2017-07-01

    Over the last 60 years, accumulating evidence has suggested that acute, chronic, and maternal Toxoplasma gondii infections predispose to schizophrenia. More recent evidence suggests that chronically infected patients with schizophrenia present with more severe disease. After acute infection, parasites form walled cysts in the brain, leading to lifelong chronic infection and drug resistance to commonly used antiparasitics. Chronic infection is the most studied and closely linked with development and severity of schizophrenia. There are currently four published randomized controlled trials evaluating antiparasitic drugs, specifically azithromycin, trimethoprim, artemisinin, and artemether, in patients with schizophrenia. No trials have demonstrated a change in psychopathology with adjunctive treatment. Published trials have either selected drugs without evidence against chronic infection or used them at doses too low to reduce brain cyst burden. Furthermore, trials have failed to achieve sufficient power or account for confounders such as previous antipsychotic treatment, sex, age, or rhesus status on antiparasitic effect. There are currently no ongoing trials of anti-Toxoplasma therapy in schizophrenia despite ample evidence to justify further testing.

  17. Induction of cell-mediated immunity during early stages of infection with intracellular protozoa

    Directory of Open Access Journals (Sweden)

    Gazzinelli R.T.

    1998-01-01

    Full Text Available Toxoplasma gondii and Trypanosoma cruzi are intracellular parasites which, as part of their life cycle, induce a potent cell-mediated immunity (CMI maintained by Th1 lymphocytes and IFN-g. In both cases, induction of a strong CMI is thought to protect the host against rapid parasite multiplication and consequent pathology and lethality during the acute phase of infection. However, the parasitic infection is not eliminated by the immune system and the vertebrate host serves as a parasite reservoir. In contrast, Leishmania sp, which is a slow growing parasite, appears to evade induction of CMI during early stages of infection as a strategy for surviving in a hostile environment (i.e., inside the macrophages which are their obligatory niche in the vertebrate host. Recent reports show that the initiation of IL-12 synthesis by macrophages during these parasitic infections is a key event in regulating CMI and disease outcome. The studies reviewed here indicate that activation/inhibition of distinct signaling pathways and certain macrophage functions by intracellular protozoa are important events in inducing/modulating the immune response of their vertebrate hosts, allowing parasite and host survival and therefore maintaining parasite life cycles.

  18. Molecular analysis of Toxoplasma gondii Surface Antigen 1 (SAG1) gene cloned from Toxoplasma gondii DNA isolated from Javanese acute toxoplasmosis

    Science.gov (United States)

    Haryati, Sri; Agung Prasetyo, Afiono; Sari, Yulia; Dharmawan, Ruben

    2018-05-01

    Toxoplasma gondii Surface Antigen 1 (SAG1) is often used as a diagnostic tool due to its immunodominant-specific as antigen. However, data of the Toxoplasma gondii SAG1 protein from Indonesian isolate is limited. To study the protein, genomic DNA was isolated from a Javanese acute toxoplasmosis blood samples patient. A complete coding sequence of Toxoplasma gondii SAG1 was cloned and inserted into an Escherichia coli expression plasmid and sequenced. The sequencing results were subjected to bioinformatics analysis. The Toxoplasma gondii SAG1 complete coding sequences were successfully cloned. Physicochemical analysis revealed the 336 aa of SAG1 had 34.7 kDa of weight. The isoelectric point and aliphatic index were 8.4 and 78.4, respectively. The N-terminal methionine half-life in Escherichia coli was more than 10 hours. The antigenicity, secondary structure, and identification of the HLA binding motifs also had been discussed. The results of this study would contribute information about Toxoplasma gondii SAG1 and benefits for further works willing to develop diagnostic and therapeutic strategies against the parasite.

  19. Intracellular survival of Staphylococcus aureus during persistent infection in the insect Tenebrio molitor.

    Science.gov (United States)

    McGonigle, John E; Purves, Joanne; Rolff, Jens

    2016-06-01

    Survival of bacteria within host cells and tissues presents a challenge to the immune systems of higher organisms. Escape from phagocytic immune cells compounds this issue, as immune cells become potential vehicles for pathogen dissemination. However, the duration of persistence within phagocytes and its contribution to pathogen load has yet to be determined. We investigate the immunological significance of intracellular persistence within the insect model Tenebrio molitor, assessing the extent, duration and location of bacterial recovery during a persistent infection. Relative abundance of Staphylococcus aureus in both intracellular and extracellular fractions was determined over 21 days, and live S. aureus were successfully recovered from both the hemolymph and within phagocytic immune cells across the entire time course. The proportion of bacteria recovered from within phagocytes also increased over time. Our results show that to accurately estimate pathogen load it is vital to account for bacteria persisting within immune cells. Copyright © 2016 Elsevier Ltd. All rights reserved.

  20. Environmental Exposures Are Important Risk Factors for Infection Toxoplasma gondii and Helicobacter pylori

    Science.gov (United States)

    Background: An estimated 70% of Americans suffer chronic infections. Helicobacter pylori and Toxoplasma gondii affect an estimated 35% and 15% of Americans, respectively. Despite their heavy burden, environmental transmission of these infections is not well understood. Object...

  1. 97 original article toxoplasma gondii infection in hiv/aids: prevalence

    African Journals Online (AJOL)

    Keywords: Toxoplasma gondii , IgG, Seroprevalence, HIV positive, CD4 cells. ... with immunosuppressive cancer and transplant ... due to active parasitaemia during pregnancy can .... especially in the night where they look for leftover.

  2. Literature Reference for Toxoplasma gondii (Applied and Environmental Microbiology. 2004. 70(7): 4035–4039)

    Science.gov (United States)

    Procedures are described for analysis of water samples and may be adapted for assessment of solid, particulate and liquid samples. The method uses real-time PCR assay for detecting Toxoplasma gondii DNA using gene-specific primers and probe.

  3. Infection rate of toxoplasma gondii and age distribution in female patients with sterility

    International Nuclear Information System (INIS)

    Li Shuhong; Dai Pei; Cui Liming; Zong Shan; Zuo Wenjing

    2006-01-01

    Objective: To discuss the relationship between the infection of Toxoplasma gondii and female sterility. Methods: Toxoplasma gondii serum antibody were determined in 882 women with sterility (experimental group) and 107 normal bearing women (control group) by using ELISA. At the same time the differences of the infection with Toxoplasma gondii between the ages of the sterility women were analyzed. Results: The positive rate in experimental group was 15.87% (140/882), the positive rate in control group was 5.61% (6/107), remarkable difference was found between two groups (P<0.01). The infection rate in the different age groups (20-24, 25-29, 30-34, 35-39 and ≥40) is 5.63%, 15.24%, 17.91%, 19.44% and 15.38%. Conclusion: Toxoplasma gondii infection may be one of the factors which can cause sterility, and the infection rates at different ages have no instinct differences. (authors)

  4. Yeast three-hybrid screen identifies TgBRADIN/GRA24 as a negative regulator of Toxoplasma gondii bradyzoite differentiation.

    Directory of Open Access Journals (Sweden)

    Anahi V Odell

    Full Text Available Differentiation of the protozoan parasite Toxoplasma gondii into its latent bradyzoite stage is a key event in the parasite's life cycle. Compound 2 is an imidazopyridine that was previously shown to inhibit the parasite lytic cycle, in part through inhibition of parasite cGMP-dependent protein kinase. We show here that Compound 2 can also enhance parasite differentiation, and we use yeast three-hybrid analysis to identify TgBRADIN/GRA24 as a parasite protein that interacts directly or indirectly with the compound. Disruption of the TgBRADIN/GRA24 gene leads to enhanced differentiation of the parasite, and the TgBRADIN/GRA24 knockout parasites show decreased susceptibility to the differentiation-enhancing effects of Compound 2. This study represents the first use of yeast three-hybrid analysis to study small-molecule mechanism of action in any pathogenic microorganism, and it identifies a previously unrecognized inhibitor of differentiation in T. gondii. A better understanding of the proteins and mechanisms regulating T. gondii differentiation will enable new approaches to preventing the establishment of chronic infection in this important human pathogen.

  5. Cryo-EM structures of the 80S ribosomes from human parasites Trichomonas vaginalis and Toxoplasma gondii

    Institute of Scientific and Technical Information of China (English)

    Zhifei Li; Qiang Guo; Lvqin Zheng; Yongsheng Ji; Yi-Ting Xie; De-Hua Lai; Zhao-Rong Lun; Xun Suo; Ning Gao

    2017-01-01

    As an indispensable molecular machine universal in all living organisms,the ribosome has been selected by evolution to be the natural target of many antibiotics and small-molecule inhibitors.High-resolution structures of pathogen ribosomes are crucial for understanding the general and unique aspects of translation control in disease-causing microbes.With cryo-electron microscopy technique,we have determined structures of the cytosolic ribosomes from two human parasites,Trichomonas vaginalis and Toxoplasma gondii,at resolution of 3.2-3.4,(A).Although the ribosomal proteins from both pathogens are typical members of eukaryotic families,with a co-evolution pattern between certain species-specific insertions/extensions and neighboring ribosomal RNA (rRNA) expansion segments,the sizes of their rRNAs are sharply different.Very interestingly,rRNAs of T.vaginalis are in size comparable to prokaryotic counterparts,with nearly all the eukaryote-specific rRNA expansion segments missing.These structures facilitate the dissection of evolution path for ribosomal proteins and RNAs,and may aid in design of novel translation inhibitors.

  6. Manipulation of host membranes by the bacterial pathogens Listeria, Francisella, Shigella and Yersinia.

    Science.gov (United States)

    Pizarro-Cerdá, Javier; Charbit, Alain; Enninga, Jost; Lafont, Frank; Cossart, Pascale

    2016-12-01

    Bacterial pathogens display an impressive arsenal of molecular mechanisms that allow survival in diverse host niches. Subversion of plasma membrane and cytoskeletal functions are common themes associated to infection by both extracellular and intracellular pathogens. Moreover, intracellular pathogens modify the structure/stability of their membrane-bound compartments and escape degradation from phagocytic or autophagic pathways. Here, we review the manipulation of host membranes by Listeria monocytogenes, Francisella tularensis, Shigella flexneri and Yersinia spp. These four bacterial model pathogens exemplify generalized strategies as well as specific features observed during bacterial infection processes. Copyright © 2016 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. The membrane as the gatekeeper of infection: Cholesterol in host-pathogen interaction.

    Science.gov (United States)

    Kumar, G Aditya; Jafurulla, Md; Chattopadhyay, Amitabha

    2016-09-01

    The cellular plasma membrane serves as a portal for the entry of intracellular pathogens. An essential step for an intracellular pathogen to gain entry into a host cell therefore is to be able to cross the cell membrane. In this review, we highlight the role of host membrane cholesterol in regulating the entry of intracellular pathogens using insights obtained from work on the interaction of Leishmania and Mycobacterium with host cells. The entry of these pathogens is known to be dependent on host membrane cholesterol. Importantly, pathogen entry is inhibited either upon depletion (or complexation), or enrichment of membrane cholesterol. In other words, an optimum level of host membrane cholesterol is necessary for efficient infection by pathogens. In this overall context, we propose a general mechanism, based on cholesterol-induced conformational changes, involving cholesterol binding sites in host cell surface receptors that are implicated in this process. A therapeutic strategy targeting modulation of membrane cholesterol would have the advantage of avoiding the commonly encountered problem of drug resistance in tackling infection by intracellular pathogens. Insights into the role of host membrane cholesterol in pathogen entry would be instrumental in the development of novel therapeutic strategies to effectively tackle intracellular pathogenesis. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  8. Behavioral changes in Rattus norvegicus coinfected by Toxocara canis and Toxoplasma gondii

    Directory of Open Access Journals (Sweden)

    Maisa Leite de Queiroz

    2013-02-01

    Full Text Available Using an elevated plus maze apparatus and an activity cage, behavioral changes in Rattus norvegicus concomitantly infected by Toxocara canis and Toxoplasma gondii were studied, during a period of 120 days. Rats infected by Toxocara canis or Toxoplasma gondii showed significant behavioral changes; however, in the group coinfected by both parasites a behavioral pattern similar to that found in the group not infected was observed thirty days after infection, suggesting the occurrence of modulation in the behavioral response.

  9. Detection of soluble antigens of Toxoplasma gondii by a four-layer modification of an enzyme immunoassay.

    OpenAIRE

    Turunen, H J

    1983-01-01

    A sensitive four-layer modification of an enzyme immunoassay for the detection of soluble antigens of Toxoplasma gondii is described. Microtiter plates were sensitized with rabbit anti-toxoplasma immunoglobulins (6 micrograms/ml) used as the primary antibodies; guinea pig anti-toxoplasma immunoglobulins (6 micrograms/ml) were used as the secondary trapping antibodies. Horseradish peroxidase-conjugated anti-guinea pig immunoglobulins were used as the indicator antibodies. The specificity of th...

  10. Assessing viability and infectivity of foodborne and waterborne stages (cysts/oocysts of Giardia duodenalis, Cryptosporidium spp., and Toxoplasma gondii: a review of methods

    Directory of Open Access Journals (Sweden)

    Rousseau Angélique

    2018-01-01

    Full Text Available Giardia duodenalis, Cryptosporidium spp. and Toxoplasma gondii are protozoan parasites that have been highlighted as emerging foodborne pathogens by the Food and Agriculture Organization of the United Nations and the World Health Organization. According to the European Food Safety Authority, 4786 foodborne and waterborne outbreaks were reported in Europe in 2016, of which 0.4% were attributed to parasites including Cryptosporidium, Giardia and Trichinella. Until 2016, no standardized methods were available to detect Giardia, Cryptosporidium and Toxoplasma (oocysts in food. Therefore, no regulation exists regarding these biohazards. Nevertheless, considering their low infective dose, ingestion of foodstuffs contaminated by low quantities of these three parasites can lead to human infection. To evaluate the risk of protozoan parasites in food, efforts must be made towards exposure assessment to estimate the contamination along the food chain, from raw products to consumers. This requires determining: (i the occurrence of infective protozoan (oocysts in foods, and (ii the efficacy of control measures to eliminate this contamination. In order to conduct such assessments, methods for identification of viable (i.e. live and infective parasites are required. This review describes the methods currently available to evaluate infectivity and viability of G. duodenalis cysts, Cryptosporidium spp. and T. gondii oocysts, and their potential for application in exposure assessment to determine the presence of the infective protozoa and/or to characterize the efficacy of control measures. Advantages and limits of each method are highlighted and an analytical strategy is proposed to assess exposure to these protozoa.

  11. Dual congenital transmission of Toxoplasma gondii and Sarcocystis neurona in a late-term aborted pup from a chronically infected southern sea otter (Enhydra lutris nereis).

    Science.gov (United States)

    Shapiro, Karen; Miller, Melissa A; Packham, Andrea E; Aguilar, Beatriz; Conrad, Patricia A; Vanwormer, Elizabeth; Murray, Michael J

    2016-03-01

    Toxoplasma gondii and Sarcocystis neurona are protozoan parasites with terrestrial definitive hosts, and both pathogens can cause fatal disease in a wide range of marine animals. Close monitoring of threatened southern sea otters (Enhydra lutris nereis) in California allowed for the diagnosis of dual transplacental transmission of T. gondii and S. neurona in a wild female otter that was chronically infected with both parasites. Congenital infection resulted in late-term abortion due to disseminated toxoplasmosis. Toxoplasma gondii and S. neurona DNA was amplified from placental tissue culture, as well as from fetal lung tissue. Molecular characterization of T. gondii revealed a Type X genotype in isolates derived from placenta and fetal brain, as well as in all tested fetal organs (brain, lung, spleen, liver and thymus). This report provides the first evidence for transplacental transmission of T. gondii in a chronically infected wild sea otter, and the first molecular and immunohistochemical confirmation of concurrent transplacental transmission of T. gondii and S. neurona in any species. Repeated fetal and/or neonatal losses in the sea otter dam also suggested that T. gondii has the potential to reduce fecundity in chronically infected marine mammals through parasite recrudescence and repeated fetal infection.

  12. Comprehensive Evaluation of Toxoplasma gondii VEG and Neospora caninum LIV Genomes with Tachyzoite Stage Transcriptome and Proteome Defines Novel Transcript Features

    KAUST Repository

    Ramaprasad, Abhinay

    2015-04-13

    Toxoplasma gondii is an important protozoan parasite that infects all warm-blooded animals and causes opportunistic infections in immuno-compromised humans. Its closest relative, Neospora caninum, is an important veterinary pathogen that causes spontaneous abortion in livestock. Comparative genomics of these two closely related coccidians has been of particular interest to identify genes that contribute to varied host cell specificity and disease. Here, we describe a manual evaluation of these genomes based on strand-specific RNA sequencing and shotgun proteomics from the invasive tachyzoite stages of these two parasites. We have corrected predicted structures of over one third of the previously annotated gene models and have annotated untranslated regions (UTRs) in over half of the predicted protein-coding genes. We observe distinctly long UTRs in both the organisms, almost four times longer than other model eukaryotes. We have also identified a putative set of cis-natural antisense transcripts (cis-NATs) and long intergenic non-coding RNAs (lincRNAs). We have significantly improved the annotation quality in these genomes that would serve as a manually curated dataset for Toxoplasma and Neospora research communities.

  13. Predator cat odors activate sexual arousal pathways in brains of Toxoplasma gondii infected rats.

    Directory of Open Access Journals (Sweden)

    Patrick K House

    Full Text Available Cat odors induce rapid, innate and stereotyped defensive behaviors in rats at first exposure, a presumed response to the evolutionary pressures of predation. Bizarrely, rats infected with the brain parasite Toxoplasma gondii approach the cat odors they typically avoid. Since the protozoan Toxoplasma requires the cat to sexually reproduce, this change in host behavior is thought to be a remarkable example of a parasite manipulating a mammalian host for its own benefit. Toxoplasma does not influence host response to non-feline predator odor nor does it alter behavior on olfactory, social, fear or anxiety tests, arguing for specific manipulation in the processing of cat odor. We report that Toxoplasma infection alters neural activity in limbic brain areas necessary for innate defensive behavior in response to cat odor. Moreover, Toxoplasma increases activity in nearby limbic regions of sexual attraction when the rat is exposed to cat urine, compelling evidence that Toxoplasma overwhelms the innate fear response by causing, in its stead, a type of sexual attraction to the normally aversive cat odor.

  14. Predator cat odors activate sexual arousal pathways in brains of Toxoplasma gondii infected rats.

    Science.gov (United States)

    House, Patrick K; Vyas, Ajai; Sapolsky, Robert

    2011-01-01

    Cat odors induce rapid, innate and stereotyped defensive behaviors in rats at first exposure, a presumed response to the evolutionary pressures of predation. Bizarrely, rats infected with the brain parasite Toxoplasma gondii approach the cat odors they typically avoid. Since the protozoan Toxoplasma requires the cat to sexually reproduce, this change in host behavior is thought to be a remarkable example of a parasite manipulating a mammalian host for its own benefit. Toxoplasma does not influence host response to non-feline predator odor nor does it alter behavior on olfactory, social, fear or anxiety tests, arguing for specific manipulation in the processing of cat odor. We report that Toxoplasma infection alters neural activity in limbic brain areas necessary for innate defensive behavior in response to cat odor. Moreover, Toxoplasma increases activity in nearby limbic regions of sexual attraction when the rat is exposed to cat urine, compelling evidence that Toxoplasma overwhelms the innate fear response by causing, in its stead, a type of sexual attraction to the normally aversive cat odor.

  15. MR imaging of intracellular and extracellular deoxyhemoglobin

    International Nuclear Information System (INIS)

    Janick, P.A.; Grossman, R.I.; Asakura, T.

    1989-01-01

    MR imaging was performed on varying concentrations of intracellular and extracellular deoxyhemoglobin as well as varying proportions of deoxyhemoglobin and oxyhemoglobin in vitro at 1.5T with use of standard spin-echo and gradient-refocused spin sequences. This study indicates that susceptibility-induced T2 shortening occurs over a broad range of intracellular deoxyhemoglobin concentrations (maximal at hematocrits between 20% and 45%), reflecting diffusional effects at the cellular level. T2* gradient-echo imaging enhances the observed hypointensity in images of intracellular deoxyhemoglobin. The characteristic MR appearance of acute hemotomas can be modeled by the behavior of intracellular and extracellular deoxyhemoglobin and oxyhemoglobin

  16. NAD+-Glycohydrolase Promotes Intracellular Survival of Group A Streptococcus.

    Directory of Open Access Journals (Sweden)

    Onkar Sharma

    2016-03-01

    Full Text Available A global increase in invasive infections due to group A Streptococcus (S. pyogenes or GAS has been observed since the 1980s, associated with emergence of a clonal group of strains of the M1T1 serotype. Among other virulence attributes, the M1T1 clone secretes NAD+-glycohydrolase (NADase. When GAS binds to epithelial cells in vitro, NADase is translocated into the cytosol in a process mediated by streptolysin O (SLO, and expression of these two toxins is associated with enhanced GAS intracellular survival. Because SLO is required for NADase translocation, it has been difficult to distinguish pathogenic effects of NADase from those of SLO. To resolve the effects of the two proteins, we made use of anthrax toxin as an alternative means to deliver NADase to host cells, independently of SLO. We developed a novel method for purification of enzymatically active NADase fused to an amino-terminal fragment of anthrax toxin lethal factor (LFn-NADase that exploits the avid, reversible binding of NADase to its endogenous inhibitor. LFn-NADase was translocated across a synthetic lipid bilayer in vitro in the presence of anthrax toxin protective antigen in a pH-dependent manner. Exposure of human oropharyngeal keratinocytes to LFn-NADase in the presence of protective antigen resulted in cytosolic delivery of NADase activity, inhibition of protein synthesis, and cell death, whereas a similar construct of an enzymatically inactive point mutant had no effect. Anthrax toxin-mediated delivery of NADase in an amount comparable to that observed during in vitro infection with live GAS rescued the defective intracellular survival of NADase-deficient GAS and increased the survival of SLO-deficient GAS. Confocal microscopy demonstrated that delivery of LFn-NADase prevented intracellular trafficking of NADase-deficient GAS to lysosomes. We conclude that NADase mediates cytotoxicity and promotes intracellular survival of GAS in host cells.

  17. Toxoplasma gondii infection in llama (Llama glama): acute visceral disseminated lesions, diagnosis, and development of tissue cysts.

    Science.gov (United States)

    Dubey, J P; Newell, T K; Verma, S K; Calero-Bernal, R; Stevens, E L

    2014-06-01

    Clinical toxoplasmosis has been reported in many species of warm-blooded animals but is rare in camelids. Here we report acute fatal systemic toxoplasmosis involving heart, thyroid gland, stomach, intestine, diaphragm, kidneys, adrenal glands, and liver of a 13-mo-old llama (Llama glama). Many Toxoplasma gondii tachyzoites were associated with tissue necrosis in multiple organs. Death was attributed to severe myocarditis. Ulcers associated with numerous tachyzoites were present in the C3 compartment of the stomach. Tissue cyst development was followed using bradyzoite-specific T. gondii antibodies. Individual intracellular, and groups of 2 or more, bradyzoites were identified in hepatocytes, biliary epithelium, myocardiocytes, lung, diaphragm, thyroid gland, spleen, and stomach. Lesions in the brain were a few microglial nodules and very early tissue cysts containing 1-3 bradyzoites. These observations suggest that the animal had acquired toxoplasmosis recently. Diagnosis was confirmed immunohistochemically by reaction with T. gondii -specific polyclonal rabbit serum but not with antibodies to the related protozoan Neospora caninum . Genetic typing using the DNA extracted from paraffin-embedded myocardium of llama and 10 PCR-restriction fragment length polymorphism (RFLP) markers revealed a type II allele at the SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, PK1 L358, and Apico loci; therefore, this isolate belongs to the ToxoDB PCR-RFLP genotype #1, which is most common in North America and Europe.

  18. [i]Toxoplasma gondii[/i] in protected wildlife in the Tatra National Park (TANAP, Slovakia

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    Ludmila Turčeková

    2014-06-01

    Full Text Available [i]Toxoplasma gondii[/i] is an obligatory intracellular protozoan parasite that infects a broad spectrum of warm-blooded vertebrate species. As a part of the food chain, farm animals play a significant role in transmission of [i]T. gondii [/i]to humans, while rats and mice serve as a main source of infection for free-living animals. The spread of toxoplasmosis in the human population is due to the interchange of the domestic and sylvatic cycles. During 2009–2011, a survey on toxoplasmosis distribution was conducted in wildlife of the Tatra National Park (TANAP in Slovakia. A total of 60 animals were examined. The presence of [i]T. gondii[/i] was detected by means of molecular methods based on TGR1E gene analyses. The highest prevalence was recorded in birds (40.0%, followed by carnivores (30.8% and rodents (18.2%. RFLP analyses of SAG2 locus confirmed in birds the genotype II and III, belonging to the avirulent strain; rodents exclusively had genotype I, characterised as a virulent train, and in carnivores all three genotypes were detected. These results present the first survey on the parasite’s occurrence in several species of free-living animals in the TANAP area. An epidemiological study confirmed the prevalence of 30.0%, implicitly referring to the level of environmental contamination with [i]T. gondii [/i]oocysts.

  19. Toxoplasma gondii chromodomain protein 1 binds to heterochromatin and colocalises with centromeres and telomeres at the nuclear periphery.

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    Mathieu Gissot

    Full Text Available BACKGROUND: Apicomplexan parasites are responsible for some of the most deadly parasitic diseases afflicting humans, including malaria and toxoplasmosis. These obligate intracellular parasites exhibit a complex life cycle and a coordinated cell cycle-dependant expression program. Their cell division is a coordinated multistep process. How this complex mechanism is organised remains poorly understood. METHODS AND FINDINGS: In this study, we provide evidence for a link between heterochromatin, cell division and the compartmentalisation of the nucleus in Toxoplasma gondii. We characterised a T. gondii chromodomain containing protein (named TgChromo1 that specifically binds to heterochromatin. Using ChIP-on-chip on a genome-wide scale, we report TgChromo1 enrichment at the peri-centromeric chromatin. In addition, we demonstrate that TgChromo1 is cell-cycle regulated and co-localised with markers of the centrocone. Through the loci-specific FISH technique for T. gondii, we confirmed that TgChromo1 occupies the same nuclear localisation as the peri-centromeric sequences. CONCLUSION: We propose that TgChromo1 may play a role in the sequestration of chromosomes at the nuclear periphery and in the process of T. gondii cell division.

  20. Toxoplasma gondii: biochemical and biophysical characterization of recombinant soluble dense granule proteins GRA2 and GRA6.

    Science.gov (United States)

    Bittame, Amina; Effantin, Grégory; Pètre, Graciane; Ruffiot, Pauline; Travier, Laetitia; Schoehn, Guy; Weissenhorn, Winfried; Cesbron-Delauw, Marie-France; Gagnon, Jean; Mercier, Corinne

    2015-03-27

    The most prominent structural feature of the parasitophorous vacuole (PV) in which the intracellular parasite Toxoplasma gondii proliferates is a membranous nanotubular network (MNN), which interconnects the parasites and the PV membrane. The MNN function remains unclear. The GRA2 and GRA6 proteins secreted from the parasite dense granules into the PV have been implicated in the MNN biogenesis. Amphipathic alpha-helices (AAHs) predicted in GRA2 and an alpha-helical hydrophobic domain predicted in GRA6 have been proposed to be responsible for their membrane association, thereby potentially molding the MMN in its structure. Here we report an analysis of the recombinant proteins (expressed in detergent-free conditions) by circular dichroism, which showed that full length GRA2 displays an alpha-helical secondary structure while recombinant GRA6 and GRA2 truncated of its AAHs are mainly random coiled. Dynamic light scattering and transmission electron microscopy showed that recombinant GRA6 and truncated GRA2 constitute a homogenous population of small particles (6-8 nm in diameter) while recombinant GRA2 corresponds to 2 populations of particles (∼8-15 nm and up to 40 nm in diameter, respectively). The unusual properties of GRA2 due to its AAHs are discussed. Copyright © 2015 Elsevier Inc. All rights reserved.

  1. Proteomics of Plant Pathogenic Fungi

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    Raquel González-Fernández

    2010-01-01

    Full Text Available Plant pathogenic fungi cause important yield losses in crops. In order to develop efficient and environmental friendly crop protection strategies, molecular studies of the fungal biological cycle, virulence factors, and interaction with its host are necessary. For that reason, several approaches have been performed using both classical genetic, cell biology, and biochemistry and the modern, holistic, and high-throughput, omic techniques. This work briefly overviews the tools available for studying Plant Pathogenic Fungi and is amply focused on MS-based Proteomics analysis, based on original papers published up to December 2009. At a methodological level, different steps in a proteomic workflow experiment are discussed. Separate sections are devoted to fungal descriptive (intracellular, subcellular, extracellular and differential expression proteomics and interactomics. From the work published we can conclude that Proteomics, in combination with other techniques, constitutes a powerful tool for providing important information about pathogenicity and virulence factors, thus opening up new possibilities for crop disease diagnosis and crop protection.

  2. Enrofloxacin is able to control Toxoplasma gondii infection in both in vitro and in vivo experimental models.

    Science.gov (United States)

    Barbosa, Bellisa Freitas; Gomes, Angelica Oliveira; Ferro, Eloisa Amália Vieira; Napolitano, Danielle Reis; Mineo, José Roberto; Silva, Neide Maria

    2012-06-08

    Currently, toxoplasmosis is treated with sulfadiazine and pyrimethamine. However, this treatment presents several adverse side effects; thus, there is a critical need for the development and evaluation of new drugs, which do not present the same problems of the standard therapy. Enrofloxacin is a fluoroquinolone antibiotic known to control infection against several bacteria in veterinary medicine. Recently, this drug has demonstrated protective effects against protozoan parasites such as Neospora caninum. The present study aimed to determine the effect of enrofloxacin in the control of Toxoplasma gondii infection. For this purpose, human foreskin fibroblast (HFF) cells were infected with T. gondii RH strain and treated with sulfadiazine, penicillin/streptomycin, pyrimethamine, or enrofloxacin. Following treatment, we analyzed the infection index, parasite intracellular proliferation and the number of plaques. Additionally, tissue parasitism and histological changes were investigated in the brain of Calomys callosus that were infected with T. gondii (ME49 strain) and treated with either sulfadiazine or enrofloxacin. Enrofloxacin was able to reduce the infection index, intracellular proliferation and the number of plaques in HFF cells infected by T. gondii in comparison with untreated or penicillin/streptomycin-treated ones. Enrofloxacin was more protective against T. gondii in HFF infected cells than sulfadiazine treatment (Penrofloxacin or the associations of sulfadiazine plus pyrimethamine, enrofloxacin plus sulfadiazine or enrofloxacin plus pyrimethamine-treatments were able to reduce the plaque numbers in HFF cells infected by T. gondii when compared to medium, penicillin/streptomycin or sulfadiazine alone. In vivo experiments demonstrated that enrofloxacin diminished significantly the tissue parasitism as well as the inflammatory alterations in the brain of C. callosus infected with T. gondii when compared with untreated animals. Based on our findings, it can

  3. Trade-Offs of Escherichia coli Adaptation to an Intracellular Lifestyle in Macrophages.

    Directory of Open Access Journals (Sweden)

    M Azevedo

    Full Text Available The bacterium Escherichia coli exhibits remarkable genomic and phenotypic variation, with some pathogenic strains having evolved to survive and even replicate in the harsh intra-macrophage environment. The rate and effects of mutations that can cause pathoadaptation are key determinants of the pace at which E. coli can colonize such niches and become pathogenic. We used experimental evolution to determine the speed and evolutionary paths undertaken by a commensal strain of E. coli when adapting to intracellular life. We estimated the acquisition of pathoadaptive mutations at a rate of 10-6 per genome per generation, resulting in the fixation of more virulent strains in less than a hundred generations. Whole genome sequencing of independently evolved clones showed that the main targets of intracellular adaptation involved loss of function mutations in genes implicated in the assembly of the lipopolysaccharide core, iron metabolism and di- and tri-peptide transport, namely rfaI, fhuA and tppB, respectively. We found a substantial amount of antagonistic pleiotropy in evolved populations, as well as metabolic trade-offs, commonly found in intracellular bacteria with reduced genome sizes. Overall, the low levels of clonal interference detected indicate that the first steps of the transition of a commensal E. coli into intracellular pathogens are dominated by a few pathoadaptive mutations with very strong effects.

  4. Delivery of rifampicin-chitin nanoparticles into the intracellular compartment of polymorphonuclear leukocytes.

    Science.gov (United States)

    Smitha, K T; Nisha, N; Maya, S; Biswas, Raja; Jayakumar, R

    2015-03-01

    Polymorphonuclear leukocytes (PMNs) provide the primary host defence against invading pathogens by producing reactive oxygen species (ROS) and microbicidal products. However, few pathogens can survive for a prolonged period of time within the PMNs. Additionally their intracellular lifestyle within the PMNs protect themselves from the additional lethal action of host immune systems such as antibodies and complements. Antibiotic delivery into the intracellular compartments of PMNs is a major challenge in the field of infectious diseases. In order to deliver antibiotics within the PMNs and for the better treatment of intracellular bacterial infections we synthesized rifampicin (RIF) loaded amorphous chitin nanoparticles (RIF-ACNPs) of 350±50 nm in diameter. RIF-ACNPs nanoparticles are found to be non-hemolytic and non-toxic against a variety of host cells. The release of rifampicin from the prepared nanoparticles was ∼60% in 24 h, followed by a sustained pattern till 72 h. The RIF-ACNPs nanoparticles showed 5-6 fold enhanced delivery of RIF into the intracellular compartments of PMNs. The RIF-ACNPs showed anti-microbial activity against Escherichia coli, Staphylococcus aureus and a variety of other bacteria. In summary, our results suggest that RIF-ACNPs could be used to treat a variety of intracellular bacterial infections. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Age-related Toxoplasma gondii seroprevalence in Dutch wild boar inconsistent with lifelong persistence of antibodies.

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    Marieke Opsteegh

    Full Text Available Toxoplasma gondii is an important zoonotic pathogen that is best known as a cause of abortion or abnormalities in the newborn after primary infection during pregnancy. Our aim was to determine the prevalence of T. gondii in wild boar to investigate the possible role of their meat in human infection and to get an indication of the environmental contamination with T. gondii. The presence of anti-T. gondii antibodies was determined by in-house ELISA in 509 wild boar shot in 2002/2003 and 464 wild boar shot in 2007. Most of the boar originated from the "Roerstreek" (n = 673 or the "Veluwe" (n = 241. A binormal mixture model was fitted to the log-transformed optical density values for wild boar up to 20 months old to estimate the optimal cut-off value (-0.685 and accompanying sensitivity (90.6% and specificity (93.6%. The overall seroprevalence was estimated at 24.4% (95% CI: 21.1-27.7%. The prevalence did not show variation between sampling years or regions, indicating a stable and homogeneous infection pressure from the environment. The relation between age and seroprevalence was studied in two stages. Firstly, seroprevalence by age group was determined by fitting the binary mixture model to 200 animals per age category. The prevalence showed a steep increase until approximately 10 months of age but stabilized at approximately 35% thereafter. Secondly, we fitted the age-dependent seroprevalence data to several SIR-type models, with seropositives as infected (I and seronegatives as either susceptible (S or resistant (R. A model with a recovery rate (SIS was superior to a model without a recovery rate (SI. This finding is not consistent with the traditional view of lifelong persistence of T. gondii infections. The high seroprevalence suggests that eating undercooked wild boar meat may pose a risk of infection with T. gondii.

  6. Toxoplasma gondii Infection Is Associated with Mitochondrial Dysfunction in-Vitro

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    Genevieve Syn

    2017-12-01

    Full Text Available Upon invasion of host cells, the ubiquitous pathogen Toxoplasma gondii manipulates several host processes, including re-organization of host organelles, to create a replicative niche. Host mitochondrial association to T. gondii parasitophorous vacuoles is rapid and has roles in modulating host immune responses. Here gene expression profiling of T. gondii infected cells reveals enrichment of genes involved in oxidative phosphorylation (OXPHOS and mitochondrial dysfunction 6 h post-infection. We identified 11 hub genes (HIF-1α, CASP8, FN1, POU5F1, CD44, ISG15, HNRNPA1, MDM2, RPL35, VHL, and NUPR1 and 10 predicted upstream regulators, including 4 endogenous regulators RICTOR, KDM5A, RB1, and D-glucose. We characterized a number of mitochondrial parameters in T. gondii infected human foreskin fibroblast cells over a 36 h time-course. In addition to the usual rapid recruitment and apparent enlargement of mitochondria around the parasitophorous vacuole we observed fragmented host mitochondria in infected cells, not linked to cellular apoptosis, from 24 h post-infection. An increase in mitochondrial superoxide levels in T. gondii infected cells was observed that required active parasite invasion and peaked at 30 h post-infection. Measurement of OXPHOS proteins showed decreased expression of Complex IV in infected cells at 24 h post-infection, followed by decreased expression of Complexes I and II at 36 h post-infection. No change occurred in Complex V. No difference in host mitochondrial membrane potential between infected and mock-infected cells was observed at any time. Our results show perturbation of host mitochondrial function following T. gondii infection that likely impacts on pathogenesis of disease.

  7. Toxoplasma gondii: infection natural congenital in cattle and an experimental inoculation of gestating cows with oocysts.

    Science.gov (United States)

    Costa, Gustavo Henrique Nogueira; da Costa, Alvimar José; Lopes, Welber Daniel Zanetti; Bresciani, Katia Denise Saraiva; dos Santos, Thais Rabelo; Esper, César Roberto; Santana, Aureo Evangelista

    2011-01-01

    Two studies, of a natural infection and an experimental infection, were performed in order to study congenital transmission of Toxoplasma gondii in cattle. In the first study, 50 fetuses were harvested from gestating cows that were eutanasied at a municipal slaughterhouse in Jaboticabal, São Paulo state, Brazil. In the second study, 11 gestating cows were divided into four groups for inoculation with T. gondii: GI consisted of three cows inoculated with 1.0 × 10(5) oocysts during their first trimester of gestation; GII consisted of three cows inoculated with 1.0 × 10(5) oocysts during their second trimester of gestation; GIII consisted of three cows inoculated with 1.0 × 10(5) oocysts during their last trimester of gestation; and GIV consisted of two control cows, one during its first and the other during its second trimester of gestation. In both studies, the presence of T. gondii was confirmed both indirectly by immunofluorescence assay (IFAT). In the natural infection experiment, 18% (9/50) of the gestating cows were confirmed to have specific antibodies (IFAT--1:64) against T. gondii. The bioassay was able to diagnose the presence of T. gondii in the tissue samples from three calves. In the second experiment, the nine cows from groups I, II and III presented with specific antibodies (IFAT) against T. gondii. In contrast, T. gondii could not be detected by IFAT, histopathological examination or the bioassay in any of the nine calves born to cows experimentally infected with T. gondii oocysts. Based on the results from both studies, we conclude that congenital infection of T. gondii in cattle, while infrequent, does occur naturally. The pathogenicity of the strain of T. gondii may influence the likelihood of this route of transmission. Copyright © 2010 Elsevier Inc. All rights reserved.

  8. Toxoplasma gondii Requires Glycogen Phosphorylase for Balancing Amylopectin Storage and for Efficient Production of Brain Cysts.

    Science.gov (United States)

    Sugi, Tatsuki; Tu, Vincent; Ma, Yanfen; Tomita, Tadakimi; Weiss, Louis M

    2017-08-29

    involved in amylopectin storage and utilization. IMPORTANCE Toxoplasma gondii is an obligate intracellular parasite that causes disease in immune-suppressed individuals, as well as a fetopathy in pregnant women who acquire infection for the first time during pregnancy. This parasite can differentiate between tachyzoites (seen in acute infection) and bradyzoites (seen in latent infection), and this differentiation is associated with disease relapse. A characteristic of bradyzoites is that they contain cytoplasmic amylopectin granules. The regulatory mechanisms and the roles of amylopectin granules during latent infection remain to be elucidated. We have identified a role of T. gondii glycogen phosphorylase (TgGP) in the regulation of starch digestion and a role of posttranslational modification of TgGP, i.e., phosphorylation of Ser25, in the regulation of amylopectin digestion. By manipulating TgGP activity in the parasite with genome editing, we found that the digestion and storage of amylopectin due to TgGP activity are both important for latency in the brain. Copyright © 2017 Sugi et al.

  9. Overcoming T. gondii infection and intracellular protein nanocapsules as biomaterials for ultrasonically controlled drug release.

    Science.gov (United States)

    Aw, M S; Paniwnyk, L

    2017-09-26

    One of the pivotal matters of concern in intracellular drug delivery is the preparation of biomaterials containing drugs that are compatible with the host target. Nanocapsules for oral delivery are found to be suitable candidates for targeting Toxoplasma gondii (T. gondii), a maneuvering and smart protozoic parasite found across Europe and America that causes a subtle but deadly infection. To overcome this disease, there is much potential of integrating protein-based cells into bioinspired nanocompartments such as via biodegradable cross-linked disulfide polyelectrolyte nanoparticles. The inner membrane vesicle system of these protein-drugs is not as simple as one might think. It is a complex transport network that includes sequential pathways, namely, endocytosis, exocytosis and autophagy. Unfortunately, the intracellular trafficking routes for nanoparticles in cells have not been extensively and intensively investigated. Hence, there lies the need to create robust protein nanocapsules for precise tracing and triggering of drug release to combat this protozoic disease. Protein nanocapsules have the advantage over other biomaterials due to their biocompatibility, use of natural ingredients, non-invasiveness, patient compliance, cost and time effectiveness. They also offer low maintenance, non-toxicity to healthy cells and a strictly defined route toward intracellular elimination through controlled drug delivery within the therapeutic window. This review covers the unprecedented opportunities that exist for constructing advanced nanocapsules to meet the growing needs arising from many therapeutic fields. Their versatile use includes therapeutic ultrasound for tumor imaging, recombinant DNA, ligand and functional group binding, the delivery of drugs and peptides via protein nanocapsules and polyelectrolytes, ultrasound-(US)-aided drug release through the gastrointestinal (GI) tract, and the recent progress in targeting tumor cells and a vast range of cancer therapies

  10. Emerging Pathogens Initiative (EPI)

    Data.gov (United States)

    Department of Veterans Affairs — The Emerging Pathogens Initiative (EPI) database contains emerging pathogens information from the local Veterans Affairs Medical Centers (VAMCs). The EPI software...

  11. Lifelong Persistence of Toxoplasma Cysts: A Questionable Dogma?

    Science.gov (United States)

    Rougier, Solène; Montoya, Jose G; Peyron, François

    2017-02-01

    It is believed that infection by Toxoplasma gondii triggers a lifelong protective immunity due to the persistence of parasitic cysts which induce immunoprotection against reinfection. A review of the scientific literature since the 1950s did not yield any definitive data regarding the duration of cysts in the host or the presence of lifelong protective immunity, which led us to question this dogma. We put forward the hypothesis that sustained immunity to T. gondii requires repeated antigenic stimulations. The decline of seroprevalence recently observed in many countries might contribute to explain the loss of immunity. We address the potential consequences of this phenomenon, should it persist and worsen. Copyright © 2016 Elsevier Ltd. All rights reserved.

  12. Outbreak of caprine abortion by Toxoplasma gondii in Midwest Brazil

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    Flávio Henrique Bravim Caldeira

    2011-11-01

    Full Text Available An outbreak of abortion by Toxoplasma gondii in goats on a farm in the Brazilian Midwest is reported. Gross lesions were not observed in seven aborted fetuses submitted to the Veterinary Pathology Laboratory, Federal University of Mato Grosso, for necropsy investigation. The main histologic lesions were mononuclear cell pneumonia and necrotizing encephalitis in varying degrees of intensity. PCR for Brucella abortus and Neospora caninum and aerobic cultures were negative in all cases. Antibody titles against T. gondii varying from 1:1024 to 1:32.768 were detected in serum samples from four aborted goats. Nested-PCR assay for T. gondii were positive in brain samples of all cases submitted. These findings indicate that T. gondii infection should be considered in the diagnosis of abortion in goats in Midwest Brazil.

  13. Bartonella and Toxoplasma Infections in Stray Cats from Iraq

    Science.gov (United States)

    Switzer, Alexandra D.; McMillan-Cole, Audrey C.; Kasten, Rickie W.; Stuckey, Matthew J.; Kass, Philip H.; Chomel, Bruno B.

    2013-01-01

    Because of overpopulation, stray/feral cats were captured on military bases in Iraq as part of the US Army Zoonotic Disease Surveillance Program. Blood samples were collected from 207 cats, mainly in Baghdad but also in North and West Iraq, to determine the prevalence of Bartonella and Toxoplasma infections. Nine (4.3%) cats, all from Baghdad, were bacteremic with B. henselae type I. Seroprevalence was 30.4% for T. gondii, 15% for B. henselae, and 12.6% for B. clarridgeiae. Differences in Bartonella prevalence by location were statistically significant, because most of the seropositive cats were from Baghdad. There was no association between T. gondii seropositivity and either of the two Bartonella species surveyed. This report is the first report on the prevalence of Bartonella and T. gondii among stray cats in Iraq, which allows for better evaluation of the zoonotic risk potential to the Iraqi people and deployed military personnel by feral cat colonies. PMID:24062480

  14. Serological study for antibodies to toxoplasma gondii in Jakarta, Indonesia.

    Science.gov (United States)

    Gandahusada, S

    1978-09-01

    A total of 280 sera from medical students, laboratory personnel from the University of Indonesia and other persons living in Jakarta were tested for antibodies to Toxoplasma gondii by the indirect hemagglutination test. Antibody titers equal to or greater than 1:256 were considered positive and were detected in 35 or 12.5% of the persons tested. The sero-positivity rates were not significant between 178 males (13.5%) and 102 females (10.8%) but were significantly different between persons of Indonesian ancestry (14.3%) and those of Chinese ancestry (2.3%). No correlation could be found between ownership of domestic cats and eating habits and positive titers.

  15. Experimental toxoplasma gondii infection in grey seals (Halichoerus grypus)

    DEFF Research Database (Denmark)

    Gajadhar, A. A.; Measures, L.; Forbes, L. B.

    2004-01-01

    Laboratory-reared animals were used to assess the susceptibility of seals (Halichoerus grypus) to Toxoplasma gondii infection. Four seals were each orally inoculated with 100 or 10,000 oocysts of T. gondii (VEG strain), and another 4 seals served as negative controls. Occasionally, mild behavioral...... changes were observed in all inoculated seals but not in control animals. A modified agglutination test revealed the presence of antibodies to T. gondii in sera collected from inoculated seals and mice inoculated as controls. No evidence of the parasite was found on an extensive histological examination...... of seal tissues, and immunohistochemical staining of tissue sections from inoculated seals revealed a single tissue cyst in only 1 seal. Control mice inoculated with 10 oocysts from the same inoculum given to seals became serologically and histologically positive for T. gondii. Cats that were fed brain...

  16. Seroepidemiologic Survey of Potential Pathogens in Obligate and Facultative Scavenging Avian Species in California

    Science.gov (United States)

    Straub, Mary H.; Kelly, Terra R.; Rideout, Bruce A.; Eng, Curtis; Wynne, Janna; Braun, Josephine; Johnson, Christine K.

    2015-01-01

    Throughout the world, populations of scavenger birds are declining rapidly with some populations already on the brink of extinction. Much of the current research into the factors contributing to these declines has focused on exposure to drug residues, lead, and other toxins. Despite increased monitoring of these declining populations, little is known about infectious diseases affecting scavenger bird species. To assess potential infectious disease risks to both obligate and facultative scavenger bird species, we performed a serosurvey for eleven potential pathogens in three species of scavenging birds in California: the California condor (Gymnogyps californianus), turkey vulture (Cathartes aura) and golden eagle (Aquila chrysaetos). California condors were seropositive for avian adenovirus, infectious bronchitis virus, Mycoplasma gallisepticum, avian paramyxovirus-2, West Nile virus (WNV) and Toxoplasma gondii. Golden eagles were seropositive for avian adenovirus, Chlamydophila psittaci and Toxoplasma gondii, and turkey vultures were seropositive for avian adenovirus, Chlamydophila psittaci, avian paramyxovirus-1, Toxoplasma gondii and WNV. Risk factor analyses indicated that rearing site and original release location were significantly associated with a positive serologic titer to WNV among free-flying condors. This study provides preliminary baseline data on infectious disease exposure in these populations for aiding in early disease detection and provides potentially critical information for conservation of the endangered California condor as it continues to expand its range and encounter new infectious disease threats. PMID:26606755

  17. Immune Evasion Strategies of Pathogens in Macrophages: the Potential for Limiting Pathogen Transmission.

    Science.gov (United States)

    Ren, Yuwei; Khan, Faheem Ahmed; Pandupuspitasari, Nuruliarizki Shinta; Zhang, Shujun

    2017-01-01

    Preventing pathogen transmission to a new host is of major interest to the immunologist and could benefit from a detailed investigation of pathogen immune evasion strategies. The first line of defense against pathogen invasion is provided by macrophages. When they sense pathogens, macrophages initiate signals to inflammatory and pro-inflammatory cytokines through pattern recognition receptors (PRRs) subsequently mediating phagocytosis and inflammation. The macrophage immune machinery classically includes two subsets: the activated M1 and the activated M2 that respond accordingly in diverse immune challenges. The lipid and glycogen metabolic pathways work together with the lysosome to help the mature phagosome to degrade and eliminate intracellular pathogens in macrophages. The viral evasion strategies are even more complex due to the interplay between autophagy and apoptosis. However, pathogens evolve several strategies to camouflage themselves against immune responses in order to ensure their survival, replication and transmission. These strategies include the muting of PRRs initiated inflammatory responses, attenuation of M1 and/or induction of M2 macrophages, suppression of autophago-lysosomal formation, interference with lipid and glycogen metabolism, and viral mediation of autophagy and apoptosis cross-talk to enhance viral replication. This review focuses on pathogen immune evasion methods and on the strategies used by the host against camouflaged pathogens.

  18. Dynamics of intracellular information decoding

    International Nuclear Information System (INIS)

    Kobayashi, Tetsuya J; Kamimura, Atsushi

    2011-01-01

    A variety of cellular functions are robust even to substantial intrinsic and extrinsic noise in intracellular reactions and the environment that could be strong enough to impair or limit them. In particular, of substantial importance is cellular decision-making in which a cell chooses a fate or behavior on the basis of information conveyed in noisy external signals. For robust decoding, the crucial step is filtering out the noise inevitably added during information transmission. As a minimal and optimal implementation of such an information decoding process, the autocatalytic phosphorylation and autocatalytic dephosphorylation (aPadP) cycle was recently proposed. Here, we analyze the dynamical properties of the aPadP cycle in detail. We describe the dynamical roles of the stationary and short-term responses in determining the efficiency of information decoding and clarify the optimality of the threshold value of the stationary response and its information-theoretical meaning. Furthermore, we investigate the robustness of the aPadP cycle against the receptor inactivation time and intrinsic noise. Finally, we discuss the relationship among information decoding with information-dependent actions, bet-hedging and network modularity

  19. Dynamics of intracellular information decoding.

    Science.gov (United States)

    Kobayashi, Tetsuya J; Kamimura, Atsushi

    2011-10-01

    A variety of cellular functions are robust even to substantial intrinsic and extrinsic noise in intracellular reactions and the environment that could be strong enough to impair or limit them. In particular, of substantial importance is cellular decision-making in which a cell chooses a fate or behavior on the basis of information conveyed in noisy external signals. For robust decoding, the crucial step is filtering out the noise inevitably added during information transmission. As a minimal and optimal implementation of such an information decoding process, the autocatalytic phosphorylation and autocatalytic dephosphorylation (aPadP) cycle was recently proposed. Here, we analyze the dynamical properties of the aPadP cycle in detail. We describe the dynamical roles of the stationary and short-term responses in determining the efficiency of information decoding and clarify the optimality of the threshold value of the stationary response and its information-theoretical meaning. Furthermore, we investigate the robustness of the aPadP cycle against the receptor inactivation time and intrinsic noise. Finally, we discuss the relationship among information decoding with information-dependent actions, bet-hedging and network modularity.

  20. HYPERTHERMIA, INTRACELLULAR FREE CALCIUM AND CALCIUM IONOPHORES

    NARCIS (Netherlands)

    STEGE, GJJ; WIERENGA, PK; KAMPINGA, HH; KONINGS, AWT

    1993-01-01

    It is shown that heat-induced increase of intracellular calcium does not correlate with hyperthermic cell killing. Six different cell lines were investigated; in four (EAT, HeLa S3, L5178Y-R and L5178Y-S) heat treatments killing 90% of the cells did not affect the levels of intracellular free

  1. Serological cross-reactivity of Trypanosoma cruzi, Ehrlichia canis, Toxoplasma gondii, Neospora caninum and Babesia canis to Leishmania infantum chagasi tests in dogs

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    Maurício Franco Zanette

    2014-01-01

    Full Text Available Introduction: The aim of this study was to evaluate the serological cross-reactivity between Leishmania sp. and other canine pathogens. Methods: Positive serum samples for Ehrlichia canis, Babesia canis, Toxoplasma gondii, Neospora caninum and Trypanosoma cruzi were tested using three serological methods enzyme linked immunosorbent assay (ELISA, indirect immunofluorescent antibody test (IFAT and Kalazar Detect™, for canine visceral leishmaniasis. Results: Of the 57 dog samples tested, 24 (42.1% tested positive using one of the three serological methods: 10/57 (17.5% for ELISA, 11/57 (19.3% for IFAT and 3/57 (5.3% for Kalazar Detect™. Conclusions: Our results demonstrated that the presence of other infectious agents may lead to cross-reactivity on leishmaniasis serological tests.

  2. Brucella abortus nicotinamidase (PncA) contributes to its intracellular replication and infectivity in mice.

    Science.gov (United States)

    Kim, Suk; Kurokawa, Daisuke; Watanabe, Kenta; Makino, Sou-Ichi; Shirahata, Toshikazu; Watarai, Masahisa

    2004-05-15

    Brucella spp. are facultative intracellular pathogens that have the ability to survive and multiply in professional and non-professional phagocytes, and cause abortion in domestic animals and undulant fever in humans. The mechanism and factors of virulence are not fully understood. Nicotinamidase/pyrazinamidase mutant (pncA mutant) of Brucella abortus failed to replicate in HeLa cells, and showed a lower rate of intracellular replication than that of wild-type strain in macrophages. Addition of nicotinic acid, but not nicotinamide, into medium supported intracellular replication of pncA mutant in HeLa cells and macrophages. The pncA mutant was not co-localizing with either late endosomes or lysosomes. The B. abortus virB4 mutant was completely cleared from the spleens of mice after 4 weeks, while the pncA mutant showed a 1.5-log reduction of the number of bacteria isolated from spleens after 10 weeks. Although pncA mutant showed reduced virulence in mice and defective intracellular replication, its ability to confer protection against the virulent B. abortus strain 544 was fully retained. These results suggest that PncA does not contribute to intracellular trafficking of B. abortus, but contributes to utilization of nutrients required for intracellular growth. Our results indicate that detailed characterizations of the pncA mutant may help the improvement of currently available live vaccines. Copyright 2004 Federation of European Microbiological Societies

  3. Seroprevalence of Toxoplasma gondii IgG antibody in HIV-infected patients at the Lagos University Teaching Hospital

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    Osunkalu VO

    2011-09-01

    Full Text Available Vincent O Osunkalu1, Sulaimon A Akanmu1, Nkolika J Ofomah1, Igwebuike V Onyiaorah2, Adewumi A Adediran1, Ralph O Akinde3, Ifeanyi A Onwuezobe41Department of Haematology and Blood Transfusion, College of Medicine Idi-Araba, Lagos, Nigeria; 2Department of Histopathology, Nnamdi Azikiwe University, Nnewi Campus, Lagos, Nigeria; 3Department of Morbid Anatomy, College of Medicine Idi-Araba, Lagos, Nigeria; 4Department of Microbiology, University of Calabar, NigeriaBackground: Toxoplasmosis is caused by infection with a ubiquitous intracellular protozoan parasite, Toxoplasma gondii. With the advent of the HIV pandemic in Nigeria, toxoplasmic encephalitis has become one of the more frequent opportunistic infections and the most commonly implicated cause of focal brain lesions complicating the course of AIDS.Objectives: This study was conducted to compare the pattern of seroprevalence of T. gondii (Toxo-IgG antibodies among HIV-infected persons presenting with neurological complications and those without.Materials and methods: Plasma specimens collected from 380 subjects were tested for Toxo-IgG antibodies by enzyme immunoassay technique and CD4 estimation by flow cytometry. Close-ended questionnaires were applied to all respondents to collect relevant data, with ethical approval from the hospital ethical committee. Plasma was obtained from two study groups comprising 300 HIV-positive respondents without neurological presentations, and 80 HIV-positive respondents with neurological complications.Results: Seroprevalence of Toxo-IgG antibodies was 58% in the HIV-positive study group without neurological complications (of these, 79.2% were males and 38.5% were females and 40% in the study group with neurological complications (46.2% of these were males and 28.6% were females. The overall seroprevalence of Toxo-IgG antibodies among the HIV-positive respondents (with and without neurological complications was 54.2% (206 of 380. Seroprevalence of Toxo

  4. Intracellular localization of Arabidopsis sulfurtransferases.

    Science.gov (United States)

    Bauer, Michael; Dietrich, Christof; Nowak, Katharina; Sierralta, Walter D; Papenbrock, Jutta

    2004-06-01

    Sulfurtransferases (Str) comprise a group of enzymes widely distributed in archaea, eubacteria, and eukaryota which catalyze the transfer of a sulfur atom from suitable sulfur donors to nucleophilic sulfur acceptors. In all organisms analyzed to date, small gene families encoding Str proteins have been identified. The gene products were localized to different compartments of the cells. Our interest concerns the localization of Str proteins encoded in the nuclear genome of Arabidopsis. Computer-based prediction methods revealed localization in different compartments of the cell for six putative AtStrs. Several methods were used to determine the localization of the AtStr proteins experimentally. For AtStr1, a mitochondrial localization was demonstrated by immunodetection in the proteome of isolated mitochondria resolved by one- and two-dimensional gel electrophoresis and subsequent blotting. The respective mature AtStr1 protein was identified by mass spectrometry sequencing. The same result was obtained by transient expression of fusion constructs with the green fluorescent protein in Arabidopsis protoplasts, whereas AtStr2 was exclusively localized to the cytoplasm by this method. Three members of the single-domain AtStr were localized in the chloroplasts as demonstrated by transient expression of green fluorescent protein fusions in protoplasts and stomata, whereas the single-domain AtStr18 was shown to be cytoplasmic. The remarkable subcellular distribution of AtStr15 was additionally analyzed by transmission electron immunomicroscopy using a monospecific antibody against green fluorescent protein, indicating an attachment to the thylakoid membrane. The knowledge of the intracellular localization of the members of this multiprotein family will help elucidate their specific functions in the organism.

  5. Intracellular calcium homeostasis and signaling.

    Science.gov (United States)

    Brini, Marisa; Calì, Tito; Ottolini, Denis; Carafoli, Ernesto

    2013-01-01

    Ca(2+) is a universal carrier of biological information: it controls cell life from its origin at fertilization to its end in the process of programmed cell death. Ca(2+) is a conventional diffusible second messenger released inside cells by the interaction of first messengers with plasma membrane receptors. However, it can also penetrate directly into cells to deliver information without the intermediation of first or second messengers. Even more distinctively, Ca(2+) can act as a first messenger, by interacting with a plasma membrane receptor to set in motion intracellular signaling pathways that involve Ca(2+) itself. Perhaps the most distinctive property of the Ca(2+) signal is its ambivalence: while essential to the correct functioning of cells, Ca(2+) becomes an agent that mediates cell distress, or even (toxic) cell death, if its concentration and movements inside cells are not carefully tuned. Ca(2+) is controlled by reversible complexation to specific proteins, which could be pure Ca(2+) buffers, or which, in addition to buffering Ca(2+), also decode its signal to pass it on to targets. The most important actors in the buffering of cell Ca(2+) are proteins that transport it across the plasma membrane and the membrane of the organelles: some have high Ca(2+) affinity and low transport capacity (e.g., Ca(2+) pumps), others have opposite properties (e.g., the Ca(2+) uptake system of mitochondria). Between the initial event of fertilization, and the terminal event of programmed cell death, the Ca(2+) signal regulates the most important activities of the cell, from the expression of genes, to heart and muscle contraction and other motility processes, to diverse metabolic pathways involved in the generation of cell fuels.

  6. Clinical significance and epidemiologic analyses of Mycobacterium avium and Mycobacterium intracellulare lung disease from post-marketing surveillance.

    Science.gov (United States)

    Suzuki, Katsuhiro; Kurashima, Atsuyuki; Tatsuno, Kinji; Kadota, Jun-Ichi

    2018-01-01

    In Japan, nontuberculous mycobacterial lung disease is mostly attributable to Mycobacterium avium complex (MAC), i.e., M. avium or M. intracellulare. However, clinical features of the disease caused by these two pathogens have not been studied sufficiently yet. A post-marketing survey of clarithromycin was performed at 130 facilities across Japan. The data on patients with M. avium infection and patients with M. intracellulare infection were selected from this survey for comparison of background variables and clinical features of the two pathogens. Among the patients analyzed (n = 368), 67.4% had M. avium infection and 32.6% had M. intracellulare infection. Stratified analysis revealed no significant differences between the ratio of the two pathogens based on gender, disease type, complication, past medical history, or smoking history. However, the percentage of patients with M. intracellulare infection was significantly higher among those with underlying lung disease than among those without lung disease (p = 0.0217). The percentage of patients with M. intracellulare infection rose significantly with age (p = 0.0296). This age-related change was more significant in women (p = 0.0018). When district-wise analysis was performed for Japan, the percentage of M. intracellulare infection was higher in the Chugoku/Shikoku and Kyushu districts whereas the percentage of M. avium infection was higher in the other districts. This survey revealed some differences in the clinical and epidemiologic features of M. avium and M. intracellulare infection. The significant predominance of M. avium infection among relatively young women is suggestive of an increase in the M. avium/M. intracellulare infection ratio among women in the future. Copyright © 2017 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.

  7. A comparative study of small RNAs in Toxoplasma gondii of distinct genotypes

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    Wang Jielin

    2012-09-01

    Full Text Available Abstract Background Toxoplasma gondii is an intracellular parasite with a significant impact on human health. Inside the mammalian and avian hosts, the parasite can undergo rapid development or remain inactive in the cysts. The mechanism that regulates parasite proliferation has not been fully understood. Small noncoding RNAs (sncRNA such as microRNAs (miRNAs are endogenous regulatory factors that can modulate cell differentiation and development. It is anticipated that hundreds of miRNAs regulate the expression of thousands of genes in a single organism. SncRNAs have been identified in T. gondii, however the profiles of sncRNAs expression and their potential regulatory function in parasites of distinct genotypes has largely been unknown. Methods The transcription profiles of miRNAs in the two genetically distinct strains, RH and ME49, of T. gondii were investigated and compared by a high-through-put RNA sequencing technique and systematic bioinformatics analysis. The expression of some of the miRNAs was confirmed by Northern blot analysis. Results 1,083,320 unique sequences were obtained. Of which, 17 conserved miRNAs related to 2 metazoan miRNA families and 339 novel miRNAs were identified. A total of 175 miRNAs showed strain-specific expression, of which 155 miRNAs were up-regulated in RH strain and 20 miRNAs were up-regulated in ME49 strain. Strain-specific expression of miRNAs in T. gondii could be due to activation of specific genes at different genomic loci or due to arm-switching of the same pre-miRNA duplex. Conclusions Evidence for the differential expression of miRNAs in the two genetically distinct strains of T. gondii has been identified and defined. MiRNAs of T. gondii are more species-specific as compared to other organisms, which can be developed as diagnostic biomarkers for toxoplasmosis. The data also provide a framework for future studies on RNAi-dependent regulatory mechanisms in the zoonotic parasite.

  8. First report of Toxoplasma gondii seroprevalence in pet parrots in China.

    Science.gov (United States)

    Zhang, Xiao-Xuan; Zhang, Nian-Zhang; Tian, Wei-Peng; Zhou, Dong-Hui; Xu, Ying-Tian; Zhu, Xing-Quan

    2014-06-01

    Toxoplasmosis, caused by the obligate intracellular protozoan parasite Toxoplasma gondii, has become a serious public health problem worldwide. T. gondii can infect almost all warm-blooded animals, including parrots. However, little is known of T. gondii infection in parrots in China. Antibodies against T. gondii in 311 parrots including 202 Budgerigars (Melopsittacus undulatus), 26 Lovebirds (Agapornis sp.), 22 Cockatiels (Nymphicus hollandicus), and 61 Alexandrine Parakeets (Psittacula eupatria) in the cities of Beijing and Weifang in north China were tested using the modified agglutination test (MAT). Twenty-six (8.36%) out of 311 serum samples were positive for T. gondii at the cutoff of 1:5. Among the four species, a higher seroprevalence of T. gondii was found in Cockatiels (13.64%, 95% confidence interval [CI] 0.00-27.98), although the difference was not statistically significant (p=0.61). Seropositivity rates against T. gondii in male parrots (10.43%, 95% CI 5.74-15.12) were not statistically different from that in female parrots (6.08%, 95% CI 2.23-9.93, p=0.17). The seropositivity of T. gondii in parrots from Weifang and Beijing was 11.11% (95% CI 6.13-16.09) and 5.70% (95% CI 2.08-9.31), respectively. The seroprevalence varied in parrots of different age groups, ranging from 5.71% (95% CI 1.27-10.15) to 13.00% (95% CI 6.41-19.69), however, the difference among age groups was not statistically significant (p=0.12). The seroprevalence of T. gondii infection in parrots in summer (11.63%, 95% CI 6.84-16.42) was significantly higher than in spring (4.32%, 95% CI 0.94-7.70, p=0.02). The results of the present survey indicated that parrots in China are exposed to T. gondii. To our knowledge, this is the first report of T. gondii seroprevalence in parrots in China.

  9. Toxoplasma gondii: prevalence and characterization of new genotypes in free-range chickens from south Brazil.

    Science.gov (United States)

    Vieira, Fernando Emmanuel Gonçalves; Sasse, João Pedro; Minutti, Ana Flávia; Miura, Ana Carolina; de Barros, Luiz Daniel; Cardim, Sergio Tosi; Martins, Thais Agostinho; de Seixas, Mércia; Yamamura, Milton Issashi; Su, Chunlei; Garcia, João Luis

    2018-03-01

    Toxoplasma gondii is an intracellular parasite that can infect all warm-blooded animals including humans. Recent studies showed that T. gondii strains from South America are genetically diverse. The present work aimed to determine T. gondii prevalence in free-ranging chicken in northwest Parana state in Brazil by two serological tests, to isolate the parasites from seropositive chickens and to genotype the isolates. Antibodies to T. gondii in 386 serum samples from 24 farms were investigated by immunofluorescence antibody assay (IFA) and modified agglutination test (MAT). Samples having titers ≥ 16 were considered positive for both tests. Among the 386 serum samples, 102 (26.4%) were positive for IFA, 64 (16.6%) were positive for MAT, 47 (12.2%) were positive in both tests, and 119 (30.8%) were positive in at least one of the two tests. Brain and pool of heart, lung, and liver from the 119 seropositive chickens were used for mouse bioassay to isolate the parasites. Thirty eight (31.9%) of these seropositive chickens were considered positives in mouse bioassay and 18 isolates were obtained. The isolates were characterized by 10 PCR-RFLP genetic markers including SAG1, SAG2 (5'-3'SAG2, alt.SAG2), SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico. Results of genotyping were compared with the genotypes in ToxoDB database. It revealed ten genotypes, including ToxoDB PCR-RFLP genotypes #6 (n = 2), #19 (n = 1), #21 (n = 2), #111 (n = 2), #152 (n = 1), and #175 (n = 1) and four new types not described before. Our results confirmed a high genetic diversity of this parasite in southern Brazil and also showed that the use of two serological tests in combination can improve the chance of T. gondii isolation. More studies should be taken to determine the zoonotic potential of chickens in the transmission of T. gondii.

  10. Seroprevalence of Toxoplasma gondii infection among patients with non-schizophrenic neurodevelopmental disorders in Alexandria, Egypt.

    Science.gov (United States)

    Shehata, Amany I; Hassanein, Faika I; Abdul-Ghani, Rashad

    2016-02-01

    Toxoplasma gondii is an opportunistic parasite with neurotropic characteristics that can mediate neurodevelopmental disorders, including mental, behavioral and personality aspects of their hosts. Therefore, the seroprevalence of anti-Toxoplasma antibodies has been studied in patients with different neurological disorders from different localities. On searching online databases, however, we could not find published studies on the seroprevalence of anti-Toxoplasma antibodies among patients with neurodevelopmental disorders in Egypt. Therefore, the present preliminary study was conducted to determine the serological profile of T. gondii infection among patients with non-schizophrenic neurodevelopmental disorders in Alexandria, Egypt. Data and blood samples were collected from 188 patients recruited for the study from four mental rehabilitation centers in the period from July 2014 to March 2015. The overall seropositivity rates of IgM and IgG among patients were 16.5% (31/188) and 50.0% (94/188), respectively. Of the studied patients' characteristics, only age was significantly associated with anti-Toxoplasma IgG seropositivity, with older patients being about twice more likely exposed to infection. However, no statistically significant association was found with IgM. In addition, seropositivity of anti-Toxoplasma IgG, but not IgM, was significantly associated with non-schizophrenic neurodevelopmental disorders; however, neither IgG nor IgM showed a significant association with cognitive impairment as indicated by the intelligence quotient scores. Copyright © 2015 Elsevier B.V. All rights reserved.

  11. SEROPREVALANCE OF TOXOPLASMA IgG AMONG PREGNANT WOMEN IN THE PROVINCE OF HATAY AND CONTRIBUTION OF AVIDITY TEST TO THE DIAGNOSE

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    Ayşe Güler Okyay

    2013-09-01

    Full Text Available Objective: Toxoplasma gondii, an obligate intracellular parasite, is a common zoonosis in the world and causes toxoplasmosis. The infection is usually asymptomatic and if it occurs during pregnancy it may cause congenital anomalies, miscarriage, stillbirth and premature delivery. In this study, determination of seroprevalance of Toxoplazma IgG and IgM among pregnant women in the province of Hatay was aimed. In addition, IgG avidity test was performed in subjects who had positive test results for both of the two antibodies. Design: In this study, 3340 pregnant women who admitted to the outpatient clinic of gynecelogy and obstetrics department of Mustafa Kemal University/Hatay between the years of 2007 and 2012were included. Toxoplazma IgM and IgG antibody test results of the subjects were examined retrospectively by screening the records of microbiology laboratory of the hospital. Additionally, IgG avidity test was performed in 114 cases whoose test results for both Toxoplazma IgM and IgG were positive. Main outcome measures: IgM and IgG seropositivity rates were found as 3.6% (n = 120 and 57% (n = 1910, respectively. The rate of new infection was detected with avidity test as 31%. Conclusions: Remarkably high seropositivity rate was observed in the Mediterranean region especially in the province of Hatay. Antibody testing for Toxoplasma gondii may be useful during routine examinations of women who are in the first trimester of pregnancy and who plan gestation. In addition, measures should be taken to raise awareness of hygiene in our region in terms of water and sanitation.

  12. AN EVALUATION STUDY OF ENZYME-LINKED IMMUNOSORBENT ASSAY (ELISA USING RECOMBINANT PROTEIN GRA1 FOR DETECTION OF IGG ANTIBODIES AGAINTS TOXOPLASMA GONDII INFECTIONS

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    Nina Difla Muflikhah

    2017-08-01

    Full Text Available Toxoplasmosis is an infectious disease caused by Toxoplasma gondii, an intracellular protozoan parasite that live inside the cells of the reticulo endothelial and parenchymal cells of human and animals (mammals and birds. Some cases of toxoplasmosis usually have no symptoms, but in any cases caused severe symptoms, such as hydrocephalus, microcephalus, intracranial calcification, retinal damage, brain abscess, mental retardation, lymphadenopathy, and others. Its severe symptoms usually showed a long time after first exposure, except symptoms showed by congenital transmission caused by infected mother. Early diagnosis is important to prevent the illness but methods for toxoplasmosis screening are still too expensive for developing country. Enzyme-linked immunosorbent assay (ELISA allow the testing of a large number samples within short time frame and based on antibody or antigen detection. This study aimed to know the sensitivity and specificity of recombinat protein GRA1 as antigen using ELISA methods. We tested the sensitivity and spesificity of GRA1 protein as antigen in ELISA methods to diagnose toxoplasmosis and compared with ELISA Kit Commercial. Reliable laboratory testing is important to detect Toxoplasma gondii infection, and focused to improving the low cost and easy-to-use diagnostic instrument. Seventy sera collected and tested using both indirect ELISA, commercial ELISA kit and GRA1 protein coated as antigen. Fourty eight and fifty one samples showed positive IgG antibody result of ELISA-GRA1 and ELISA kit. Negative sample tested by ELISA-GRA1 was 22 samples and 19 sample tested by ELISA Kit. The sensitivity and specificity of GRA1-based on ELISA were 100% and 86.36%, positive prediction value (ppv was 94.11%. These data indicate that the recombinant protein GRA1 is a highly immunogenic protein in human toxoplasmosis and become a promising marker for the screening of toxoplasmosis.

  13. Biological macromolecules based targeted nanodrug delivery systems for the treatment of intracellular infections.

    Science.gov (United States)

    Aparna, V; Shiva, M; Biswas, Raja; Jayakumar, R

    2018-04-15

    Intracellular infections are tricky to treat, the reason being the poor penetration of antibiotics/antimycotics into the microbial niche (host cell). Macrophages are primary targets of facultative and obligate intracellular bacteria/fungi to be abused as host cells. The need for drugs with better intracellular penetration led to the development of endocytosable drug carriers, which can cross the cell membrane of the host cells (macrophages) by imitating the entry path of the pathogens. Therefore, the drugs can be targeted to macrophages ensuring enhanced therapeutic effect. This review discusses the exploitation of various nanocarriers for targeted delivery of drugs to the macrophages in the last two decades. Copyright © 2018 Elsevier B.V. All rights reserved.

  14. Delineation of diverse macrophage activation programs in response to intracellular parasites and cytokines.

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    Shuyi Zhang

    2010-03-01

    Full Text Available The ability to reside and proliferate in macrophages is characteristic of several infectious agents that are of major importance to public health, including the intracellular parasites Trypanosoma cruzi (the etiological agent of Chagas disease and Leishmania species (etiological agents of Kala-Azar and cutaneous leishmaniasis. Although recent studies have elucidated some of the ways macrophages respond to these pathogens, the relationships between activation programs elicited by these pathogens and the macrophage activation programs elicited by bacterial pathogens and cytokines have not been delineated.To provide a global perspective on the relationships between macrophage activation programs and to understand how certain pathogens circumvent them, we used transcriptional profiling by genome-wide microarray analysis to compare the responses of mouse macrophages following exposure to the intracellular parasites T. cruzi and Leishmania mexicana, the bacterial product lipopolysaccharide (LPS, and the cytokines IFNG, TNF, IFNB, IL-4, IL-10, and IL-17. We found that LPS induced a classical activation state that resembled macrophage stimulation by the Th1 cytokines IFNG and TNF. However, infection by the protozoan pathogen L. mexicana produced so few transcriptional changes that the infected macrophages were almost indistinguishable from uninfected cells. T. cruzi activated macrophages produced a transcriptional signature characterized by the induction of interferon-stimulated genes by 24 h post-infection. Despite this delayed IFN response by T. cruzi, the transcriptional response of macrophages infected by the kinetoplastid pathogens more closely resembled the transcriptional response of macrophages stimulated by the cytokines IL-4, IL-10, and IL-17 than macrophages stimulated by Th1 cytokines.This study provides global gene expression data for a diverse set of biologically significant pathogens and cytokines and identifies the relationships between

  15. Toxoplasma gondii infection in workers occupationally exposed to unwashed raw fruits and vegetables: a case control seroprevalence study

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    Alvarado-Esquivel Cosme

    2011-12-01

    Full Text Available Abstract Background Through a case control seroprevalence study, we sought to determine the association of Toxoplasma gondii infection with occupational exposure to unwashed raw fruits and vegetables. Methods Subjects, numbering 200, who worked growing or selling fruits and vegetables, and 400 control subjects matched by age, gender, and residence were examined by enzyme immunoassays for the presence of anti-Toxoplasma IgG and IgM antibodies. Socio-demographic, clinical, and behavioral characteristics from the study subjects were obtained. Results Of the 200 fruit and vegetable workers, 15 (7.5% of whom, and 31 (7.8% of the 400 controls were positive for anti-Toxoplasma IgG antibodies (P = 0.96. Anti-Toxoplasma IgM antibodies were found in 2 (1% of the fruit workers and in 11 (2.8% of the control subjects (P = 0.23. Seroprevalence of Toxoplasma antibodies increased with age (P = 0.0004. In addition, seropositivity to Toxoplasma was associated with ill status (P = 0.04, chronic tonsillitis (P = 0.03, and reflex impairment (P = 0.03. Multivariate analysis showed that Toxoplasma infection was associated with consumption of raw meat (OR = 5.77; 95% CI: 1.15-28.79; P = 0.03, unwashed raw fruits (OR = 2.50; 95% CI: 1.11-5.63; P = 0.02, and living in a house with soil floors (OR = 3.10; 95% CI: 1.22-7.88; P = 0.01, whereas Toxoplasma infection was negatively associated with traveling abroad (OR = 0.28; 95% CI: 0.12-0.67; P = 0.005. Conclusions This is the first report of seroprevalence and contributing factors for Toxoplasma infection in workers occupationally exposed to unwashed raw fruits and vegetables, and the results may help in the design of optimal preventive measures against Toxoplasma infection especially in female workers at reproductive age.

  16. Nanoparticles for intracellular-targeted drug delivery

    International Nuclear Information System (INIS)

    Paulo, Cristiana S O; Pires das Neves, Ricardo; Ferreira, Lino S

    2011-01-01

    Nanoparticles (NPs) are very promising for the intracellular delivery of anticancer and immunomodulatory drugs, stem cell differentiation biomolecules and cell activity modulators. Although initial studies in the area of intracellular drug delivery have been performed in the delivery of DNA, there is an increasing interest in the use of other molecules to modulate cell activity. Herein, we review the latest advances in the intracellular-targeted delivery of short interference RNA, proteins and small molecules using NPs. In most cases, the drugs act at different cellular organelles and therefore the drug-containing NPs should be directed to precise locations within the cell. This will lead to the desired magnitude and duration of the drug effects. The spatial control in the intracellular delivery might open new avenues to modulate cell activity while avoiding side-effects.

  17. Biological synthesis and characterization of intracellular gold ...

    Indian Academy of Sciences (India)

    thods of reduction of metal ions using plants or microorganisms are often ... have several advantages over bacteria, they are often pre- ferred. ... in static condition for a period of 7 days. ... work was focused on the production of intracellular gold.

  18. Calcium signaling in closely related protozoan groups (Alveolata): non-parasitic ciliates (Paramecium, Tetrahymena) vs. parasitic Apicomplexa (Plasmodium, Toxoplasma).

    Science.gov (United States)

    Plattner, H; Sehring, I M; Mohamed, I K; Miranda, K; De Souza, W; Billington, R; Genazzani, A; Ladenburger, E-M

    2012-05-01

    The importance of Ca2+-signaling for many subcellular processes is well established in higher eukaryotes, whereas information about protozoa is restricted. Recent genome analyses have stimulated such work also with Alveolates, such as ciliates (Paramecium, Tetrahymena) and their pathogenic close relatives, the Apicomplexa (Plasmodium, Toxoplasma). Here we compare Ca2+ signaling in the two closely related groups. Acidic Ca2+ stores have been characterized in detail in Apicomplexa, but hardly in ciliates. Two-pore channels engaged in Ca2+-release from acidic stores in higher eukaryotes have not been stingently characterized in either group. Both groups are endowed with plasma membrane- and endoplasmic reticulum-type Ca2+-ATPases (PMCA, SERCA), respectively. Only recently was it possible to identify in Paramecium a number of homologs of ryanodine and inositol 1,3,4-trisphosphate receptors (RyR, IP3R) and to localize them to widely different organelles participating in vesicle trafficking. For Apicomplexa, physiological experiments suggest the presence of related channels although their identity remains elusive. In Paramecium, IP3Rs are constitutively active in the contractile vacuole complex; RyR-related channels in alveolar sacs are activated during exocytosis stimulation, whereas in the parasites the homologous structure (inner membrane complex) may no longer function as a Ca2+ store. Scrutinized comparison of the two closely related protozoan phyla may stimulate further work and elucidate adaptation to parasitic life. See also "Conclusions" section. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. Effect of Macrophage Migration Inhibitory Factor (MIF) in Human Placental Explants Infected with Toxoplasma gondii Depends on Gestational Age

    Science.gov (United States)

    de Oliveira Gomes, Angelica; de Oliveira Silva, Deise Aparecida; Silva, Neide Maria; de Freitas Barbosa, Bellisa; Franco, Priscila Silva; Angeloni, Mariana Bodini; Fermino, Marise Lopes; Roque-Barreira, Maria Cristina; Bechi, Nicoletta; Paulesu, Luana Ricci; dos Santos, Maria Célia; Mineo, José Roberto; Ferro, Eloisa Amália Vieira

    2011-01-01

    Because macrophage migration inhibitory factor (MIF) is a key cytokine in pregnancy and has a role in inflammatory response and pathogen defense, the objective of the present study was to investigate the effects of MIF in first- and third-trimester human placental explants infected with Toxoplasma gondii. Explants were treated with recombinant MIF, IL-12, interferon-γ, transforming growth factor-β1, or IL-10, followed by infection with T. gondii RH strain tachyzoites. Supernatants of cultured explants were assessed for MIF production. Explants were processed for morphologic analysis, immunohistochemistry, and real-time PCR analysis. Comparison of infected and stimulated explants versus noninfected control explants demonstrated a significant increase in MIF release in first-trimester but not third-trimester explants. Tissue parasitism was higher in third- than in first-trimester explants. Moreover, T. gondii DNA content was lower in first-trimester explants treated with MIF compared with untreated explants. However, in third-trimester explants, MIF stimulus decreased T. gondii DNA content only at the highest concentration of the cytokine. In addition, high expression of MIF receptor was observed in first-trimester placental explants, whereas MIF receptor expression was low in third-trimester explants. In conclusion, MIF was up-regulated and demonstrated to be important for control of T. gondii infection in first-trimester explants, whereas lack of MIF up-regulation in third-trimester placentas may be involved in higher susceptibility to infection at this gestational age. PMID:21641401

  20. Occurrence of antibodies anti -Toxoplasma gondii, Neospora caninum and Leptospira interrogans in a captive deer herd in Southern Brazil

    Directory of Open Access Journals (Sweden)

    Cristina Kraemer Zimpel

    Full Text Available Abstract A large number of Brazilian zoos keep many endangered species of deer, however, very few disease surveillance studies have been conducted among captive cervids. Blood samples from 32 Brazilian deer (Blastocerus dichotomus, Mazama nana and Mazama americana kept in captivity at Bela Vista Biological Sanctuary (Foz do Iguaçu, Brazil were investigated for 10 ruminant pathogens, with the aims of monitoring deer health status and evaluating any potential zoonotic risk. Deer serum samples were tested for Brucella abortus, Leptospira (23 serovars, Toxoplasma gondii, Neospora caninum, bovine viral diarrhea virus, infectious bovine rhinotracheitis virus, foot-and-mouth disease virus, western equine encephalitis virus, eastern equine encephalitis virus and Venezuelan equine encephalitis virus. Antibodies against T. gondii (15.6%, N. caninum (6.2% and L. interrogans serogroup Serjoe (3.1% were detected. The serological results for all other infectious agents were negative. The deer were considered to be clinically healthy and asymptomatic regarding any disease. Compared with studies on free-ranging deer, the prevalences of the same agents tested among the captive deer kept at the Sanctuary were lower, thus indicating good sanitary conditions and high-quality management practices at the zoo.

  1. Incidence of adult brain cancers is higher in countries where the protozoan parasite Toxoplasma gondii is common

    Science.gov (United States)

    Thomas, Frédéric; Lafferty, Kevin D.; Brodeur, Jacques; Elguero, Eric; Gauthier-Clerc, Michel; Missé, Dorothée

    2012-01-01

    We explored associations between the common protozoan parasite Toxoplasma gondii and brain cancers in human populations. We predicted that T. gondii could increase the risk of brain cancer because it is a long-lived parasite that encysts in the brain, where it provokes inflammation and inhibits apoptosis. We used a medical geography approach based on the national incidence of brain cancers and seroprevalence of T. gondii. We corrected reports of incidence for national gross domestic product because wealth probably increases the ability to detect cancer. We also included gender, cell phone use and latitude as variables in our initial models. Prevalence of T. gondii explained 19 per cent of the residual variance in brain cancer incidence after controlling for the positive effects of gross domestic product and latitude among nations. Infection with T. gondii was associated with a 1.8-fold increase in the risk of brain cancers across the range of T. gondii prevalence in our dataset (4–67%). These results, though correlational, suggest that T. gondii should be investigated further as a possible oncogenic pathogen of humans.

  2. Effector-triggered immunity: from pathogen perception to robust defense.

    Science.gov (United States)

    Cui, Haitao; Tsuda, Kenichi; Parker, Jane E

    2015-01-01

    In plant innate immunity, individual cells have the capacity to sense and respond to pathogen attack. Intracellular recognition mechanisms have evolved to intercept perturbations by pathogen virulence factors (effectors) early in host infection and convert it to rapid defense. One key to resistance success is a polymorphic family of intracellular nucleotide-binding/leucine-rich-repeat (NLR) receptors that detect effector interference in different parts of the cell. Effector-activated NLRs connect, in various ways, to a conserved basal resistance network in order to transcriptionally boost defense programs. Effector-triggered immunity displays remarkable robustness against pathogen disturbance, in part by employing compensatory mechanisms within the defense network. Also, the mobility of some NLRs and coordination of resistance pathways across cell compartments provides flexibility to fine-tune immune outputs. Furthermore, a number of NLRs function close to the nuclear chromatin by balancing actions of defense-repressing and defense-activating transcription factors to program cells dynamically for effective disease resistance.

  3. PKC-η-MARCKS Signaling Promotes Intracellular Survival of Unopsonized Burkholderia thailandensis.

    Science.gov (United States)

    Micheva-Viteva, Sofiya N; Shou, Yulin; Ganguly, Kumkum; Wu, Terry H; Hong-Geller, Elizabeth

    2017-01-01

    Pathogenic Burkholderia rely on host factors for efficient intracellular replication and are highly refractory to antibiotic treatment. To identify host genes that are required by Burkholderia spp. during infection, we performed a RNA interference (RNAi) screen of the human kinome and identified 35 host kinases that facilitated Burkholderia thailandensis intracellular survival in human monocytic THP-1 cells. We validated a selection of host kinases using imaging flow cytometry to assess efficiency of B. thailandensis survival in the host upon siRNA-mediated knockdown. We focused on the role of the novel protein kinase C isoform, PKC-η, in Burkholderia infection and characterized PKC-η/MARCKS signaling as a key event that promotes the survival of unopsonized B. thailandensis CDC2721121 within host cells. While infection of lung epithelial cells with unopsonized Gram-negative bacteria stimulated phosphorylation of Ser175/160 in the MARCKS effector domain, siRNA-mediated knockdown of PKC-η expression reduced the levels of phosphorylated MARCKS by >3-fold in response to infection with Bt CDC2721121. We compared the effect of the conventional PKC-α and novel PKC-η isoforms on the growth of B. thailandensis CDC2721121 within monocytic THP-1 cells and found that ≥75% knock-down of PRKCH transcript levels reduced intracellular bacterial load 100% more efficiently when compared to growth in cells siRNA-depleted of the classical PKC-α, suggesting that the PKC-η isoform can specifically mediate Burkholderia intracellular survival. Based on imaging studies of intracellular B. thailandensis , we found that PKC-η function stimulates phagocytic pathways that promote B. thailandensis escape into the cytoplasm leading to activation of autophagosome flux. Identification of host kinases that are targeted by Burkholderia during infection provides valuable molecular insights in understanding Burkholderia pathogenesis, and ultimately, in designing effective host

  4. The Propeptide of the Metalloprotease of Listeria monocytogenes Controls Compartmentalization of the Zymogen during Intracellular Infection▿

    OpenAIRE

    O'Neil, Heather S.; Forster, Brian M.; Roberts, Kari L.; Chambers, Andrew J.; Bitar, Alan Pavinski; Marquis, Hélène

    2009-01-01

    Integral to the virulence of the intracellular bacterial pathogen Listeria monocytogenes is its metalloprotease (Mpl). Mpl regulates the activity and compartmentalization of the bacterial broad-range phospholipase C (PC-PLC). Mpl is secreted as a proprotein that undergoes intramolecular autocatalysis to release its catalytic domain. In related proteases, the propeptide serves as a folding catalyst and can act either in cis or in trans. Propeptides can also influence protein compartmentalizati...

  5. Mycobacterium intracellulare Infection Mimicking Progression of Scleroderma

    DEFF Research Database (Denmark)

    Krabbe, Simon; Engelhart, Merete; Thybo, Sören

    2017-01-01

    This case report describes a patient with scleroderma who developed Mycobacterium intracellulare infection, which for more than a year mimicked worsening of her connective tissue disorder. The patient was diagnosed with scleroderma based on puffy fingers that developed into sclerodactyly, abnormal......, unfortunately with significant scarring. Immunodeficiency testing was unremarkable. In summary, an infection with Mycobacterium intracellulare was mistaken for an unusually severe progression of scleroderma....

  6. Cyclic AMP Pathway Activation and Extracellular Zinc Induce Rapid Intracellular Zinc Mobilization in Candida albicans

    Science.gov (United States)

    Kjellerup, Lasse; Winther, Anne-Marie L.; Wilson, Duncan; Fuglsang, Anja T.

    2018-01-01

    Zinc is an essential micronutrient, required for a range of zinc-dependent enzymes and transcription factors. In mammalian cells, zinc serves as a second messenger molecule. However, a role for zinc in signaling has not yet been established in the fungal kingdom. Here, we used the intracellular zinc reporter, zinbo-5, which allowed visualization of zinc in the endoplasmic reticulum and other components of the internal membrane system in Candida albicans. We provide evidence for a link between cyclic AMP/PKA- and zinc-signaling in this major human fungal pathogen. Glucose stimulation, which triggers a cyclic AMP spike in this fungus resulted in rapid intracellular zinc mobilization and this “zinc flux” could be stimulated with phosphodiesterase inhibitors and blocked via inhibition of adenylate cyclase or PKA. A similar mobilization of intracellular zinc was generated by stimulation of cells with extracellular zinc and this effect could be reversed with the chelator EDTA. However, zinc-induced zinc flux was found to be cyclic AMP independent. In summary, we show that activation of the cyclic AMP/PKA pathway triggers intracellular zinc mobilization in a fungus. To our knowledge, this is the first described link between cyclic AMP signaling and zinc homeostasis in a human fungal pathogen. PMID:29619016

  7. Toxoplasma gondii infection reduces predator aversion in rats through epigenetic modulation in the host medial amygdala.

    Science.gov (United States)

    Hari Dass, Shantala Arundhati; Vyas, Ajai

    2014-12-01

    Male rats (Rattus novergicus) infected with protozoan Toxoplasma gondii relinquish their innate aversion to the cat odours. This behavioural change is postulated to increase transmission of the parasite to its definitive felid hosts. Here, we show that the Toxoplasma gondii infection institutes an epigenetic change in the DNA methylation of the arginine vasopressin promoter in the medial amygdala of male rats. Infected animals exhibit hypomethylation of arginine vasopressin promoter, leading to greater expression of this nonapeptide. The infection also results in the greater activation of the vasopressinergic neurons after exposure to the cat odour. Furthermore, we show that loss of fear in the infected animals can be rescued by the systemic hypermethylation and recapitulated by directed hypomethylation in the medial amygdala. These results demonstrate an epigenetic proximate mechanism underlying the extended phenotype in the Rattus novergicus-Toxoplasma gondii association. © 2014 John Wiley & Sons Ltd.

  8. T3SS effector VopL inhibits the host ROS response, promoting the intracellular survival of Vibrio parahaemolyticus.

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    Marcela de Souza Santos

    2017-06-01

    Full Text Available The production of antimicrobial reactive oxygen species by the nicotinamide dinucleotide phosphate (NADPH oxidase complex is an important mechanism for control of invading pathogens. Herein, we show that the gastrointestinal pathogen Vibrio parahaemolyticus counteracts reactive oxygen species (ROS production using the Type III Secretion System 2 (T3SS2 effector VopL. In the absence of VopL, intracellular V. parahaemolyticus undergoes ROS-dependent filamentation, with concurrent limited growth. During infection, VopL assembles actin into non-functional filaments resulting in a dysfunctional actin cytoskeleton that can no longer mediate the assembly of the NADPH oxidase at the cell membrane, thereby limiting ROS production. This is the first example of how a T3SS2 effector contributes to the intracellular survival of V. parahaemolyticus, supporting the establishment of a protective intracellular replicative niche.

  9. A method for functional trans-complementation of intracellular Francisella tularensis.

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    Shaun Steele

    Full Text Available Francisella tularensis is a highly infectious bacterial pathogen that invades and replicates within numerous host cell types. After uptake, F. tularensis bacteria escape the phagosome, replicate within the cytosol, and suppress cytokine responses. However, the mechanisms employed by F. tularensis to thrive within host cells are mostly unknown. Potential F. tularensis mutants involved in host-pathogen interactions are typically discovered by negative selection screens for intracellular replication or virulence. Mutants that fulfill these criteria fall into two categories: mutants with intrinsic intracellular growth defects and mutants that fail to modify detrimental host cell processes. It is often difficult and time consuming to discriminate between these two possibilities. We devised a method to functionally trans-complement and thus identify mutants that fail to modify the host response. In this assay, host cells are consistently and reproducibly infected with two different F. tularensis strains by physically tethering the bacteria to antibody-coated beads. To examine the efficacy of this protocol, we tested phagosomal escape, cytokine suppression, and intracellular replication for F. tularensis ΔripA and ΔpdpC. ΔripA has an intracellular growth defect that is likely due to an intrinsic defect and fails to suppress IL-1β secretion. In the co-infection model, ΔripA was unable to replicate in the host cell when wild-type bacteria infected the same cell, but cytokine suppression was rescued. Therefore, ΔripA intracellular growth is due to an intrinsic bacterial defect while cytokine secretion results from a failed host-pathogen interaction. Likewise, ΔpdpC is deficient for phagosomal escape, intracellular survival and suppression of IL-1β secretion. Wild-type bacteria that entered through the same phagosome as ΔpdpC rescued all of these phenotypes, indicating that ΔpdpC failed to properly manipulate the host. In summary, functional

  10. Prevalence of Toxoplasma gondii in Canadian market-age pigs.

    Science.gov (United States)

    Gajadhar, A A; Aramini, J J; Tiffin, G; Bisaillon, J R

    1998-08-01

    During 1991 and 1992, 2,800 market-age pigs were sampled at federally inspected abattoirs from across Canada. Anti-Toxoplasma gondii IgG at titers of > or =1:32 were found in 240 pigs examined by a commercial, latex agglutination test. Seroprevalences ranged from 3.5 to 13.2% in the different regions of the country. Tissue hybridization studies using a previously developed probe demonstrated T. gondii ribosomal RNA in 9 of 36 animals, whereas mouse bioassay testing of heart muscle and diaphragm from all 2,800 pigs failed to demonstrate the presence of infective stages of T. gondii in tissues. Although serology results from this study indicated that Canadian market-age pigs are infected with T. gondii at rates similar to those reported from other parts of North America, mouse bioassay results suggested that Canadian pork products contain low levels of infective organisms. This apparent discrepancy suggests that serological evidence of T. gondii infection in pigs alone does not accurately assess the public health risks associated with consuming improperly cooked pork products.

  11. Meat juice serology for Toxoplasma gondii infection in chickens

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    Alice Vismarra

    2016-01-01

    Full Text Available Toxoplasma gondii is an important foodborne zoonosis. Free-range chickens are at particularly high risk of infection and are also excellent indicators of soil contamination by oocysts. In the present study, hearts of 77 freerange chickens were collected at slaughter. T. gondii meat juice enzyme-linked immunosorbent assay was performed with a commercial kit, following validation with positive controls, from experimentally infected chickens, and negative ones. Out of 77 samples, only 66 gave sufficient meat juice for serology. Of these, 24 (36.4% were positive for T. gondii considering the 5*standard deviation values (calculated on the optical density of negative controls, while all the samples were negative considering sample/positive% values. Parasite-specific polymerase chain reaction was carried out on all samples obtained from heart tissue and none were positive for the presence of T. gondii DNA. Results would suggest that further study on the use of meat juice with a validated serological test to detect T. gondii in chickens could lead to widespread epidemiological studies in this important intermediate host. However, sample collection and test specificity require further evaluation.

  12. Seroprevalence of Toxoplasma gondii infection in Norwegian dairy goats

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    Stormoen Marit

    2012-12-01

    Full Text Available Abstract Background Toxoplasma gondii is a major problem for the sheep industry as it may cause reproduction problems. The importance of T. gondii in Norwegian goat herds is uncertain, but outbreaks of toxoplasmosis in dairy goat farms have been recorded. The aim of this study was to describe the prevalence of T. gondii infection in Norwegian dairy goats by using serology. Findings Goat serum originally collected as part of two nationwide surveillance and control programmes between 2002 and 2008 were examined for T. gondii antibodies by using direct agglutination test. In total, 55 of 73 herds (75% had one or more serologically positive animals, while 377 of 2188 (17% of the individual samples tested positive for T. gondii antibodies. Conclusions This is the first prevalence study of T. gondii infection in Norwegian goats. The results show that Norwegian goat herds are commonly exposed to T. gondii. Nevertheless, the majority of goat herds have a low prevalence of antibody positive animals, which make them vulnerable to infections with T. gondii during the gestation period.

  13. Detection of Toxoplasma gondii DNA in Brazilian oysters (Crassostrea rhizophorae).

    Science.gov (United States)

    Ribeiro, L A; Santos, L K N S S; Brito, P A; Maciel, B M; Da Silva, A V; Albuquerque, G R

    2015-05-04

    The aim of this study was to detect evidence of Toxoplasma gondii using polymerase chain reaction (PCR)-based techniques in oysters (Crassostrea rhizophorae) obtained from the southern coastal region of Bahia, Brazil. A total of 624 oysters were collected, and the gills and digestive glands were dissected. Each tissue sample was separated into pools containing tissues (of the same type) from three animals, leading to a total of 416 experimental samples for analysis (208 samples each from the gills and digestive glands). Molecular analysis using PCR-based detection of the T. gondii AF 146527 repetitive fragment yielded negative results for all samples. However, when nested-PCR was used for detection of the T. gondii SAG-1 gene, 17 samples were positive, with the gills being the tissue with maximal detection of the parasite. These positive results were confirmed by sample sequencing. It is therefore suggested that C. rhizophorae oysters are capable of filtering and retaining T. gondii oocysts in their tissue. This represents a risk to public health because they are traditionally ingested in natura.

  14. Toxoplasma gondii: II. Tachyzoite antigenic characterization of eigth strains

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    Regina Mitsuka

    1998-01-01

    Full Text Available Eight Toxoplasma gondii strains were analyzed using ELISA and Western blot techniques, in order to demonstrate possible immunological differences. The analyzed strains were: LIV IV, LIV V and S 11 isolated from swine, RH and VPS from a human being, AS 28 from a wild mouse, HV III from a dog and CN from a cat. With the ELISA assay the eight strains showed similar reactivity with homologous and heterologous sera. The antigenic suspension, consisting of total cellular extract of tachyzoites, was effective in the indirect ELISA assay, with the positive sera reacting strongly and the negative not reacting with the antigens. The Western blot analysis showed that the T. gondii strains have similar antigenic profiles with a few variations. Three bands were observed in all strains: one of about 33 kDa (p33, another of 54 kDa (p54 and a third one of 66 kDa (p66. The HV III strain, isolated from a dog, did not show three antigens (50, 70 and 75 kDa that were present in the others. However, this difference was not detected by the ELISA assay. Only two antigens (62 kDa of the CN and 67 kDa of the LIV IV were strain-specific antigens.

  15. A unique dual activity amino acid hydroxylase in Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Gaskell

    Full Text Available The genome of the protozoan parasite Toxoplasma gondii was found to contain two genes encoding tyrosine hydroxylase; that produces L-DOPA. The encoded enzymes metabolize phenylalanine as well as tyrosine with substrate preference for tyrosine. Thus the enzymes catabolize phenylalanine to tyrosine and tyrosine to L-DOPA. The catalytic domain descriptive of this class of enzymes is conserved with the parasite enzyme and exhibits similar kinetic properties to metazoan tyrosine hydroxylases, but contains a unique N-terminal extension with a signal sequence motif. One of the genes, TgAaaH1, is constitutively expressed while the other gene, TgAaaH2, is induced during formation of the bradyzoites of the cyst stages of the life cycle. This is the first description of an aromatic amino acid hydroxylase in an apicomplexan parasite. Extensive searching of apicomplexan genome sequences revealed an ortholog in Neospora caninum but not in Eimeria, Cryptosporidium, Theileria, or Plasmodium. Possible role(s of these bi-functional enzymes during host infection are discussed.

  16. Toxoplasma gondii in wild and domestic animals from New Caledonia

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    Roqueplo C.

    2011-11-01

    Full Text Available Samples (serum or meat juice collected from 205 animals in New Caledonia in April 2009 were tested for antibodies against Toxoplasma gondii by ELISA using the multi-species ID Screen® Toxoplasmosis Indirect kit (IDVET, Montpellier. Antibodies to T. gondii were detected in 2% (1/49 of the pigs, in 3.3% (1/30 of the cattle, in 13.8% (4/29 of Rusa deers, in 16% (4/25 of the horses, in 32.8% (21/64 of the dogs, and in 50% (4/8 of cats. Statistically, no significant difference was observed between T. gondii seroprevalence and age or sex. No survey on the prevalence of T. gondii in animals has ever been conducted in New Caledonia and this is the first serological evidence of T. gondii in Rusa deer (Cervus timorensis russa. These results indicate an important circulation of T. gondii exists in the animal populations of New Caledonia. In view of humans being exposed, it is advisable to insist on sanitary education and on respect for good hygienic and food practice.

  17. Current Treatment of Toxoplasma Retinochoroiditis: An Evidence-Based Review

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    Meredith Harrell

    2014-01-01

    Full Text Available Objective. To perform an evidence-based review of treatments for Toxoplasma retinochoroiditis (TRC. Methods. A systematic literature search was performed using the PubMed database and the key phrase “ocular toxoplasmosis treatment” and the filter for “controlled clinical trial” and “randomized clinical trial” as well as OVID medline (1946 to May week 2 2014 using the keyword ‘‘ocular toxoplasmosis’’. The included studies were used to evaluate the various treatment modalities of TRC. Results. The electronic search yielded a total of 974 publications of which 44 reported on the treatment of ocular toxoplasmosis. There were 9 randomized controlled studies and an additional 3 comparative studies on the treatment of acute TRC with systemic or intravitreous antibiotics or on reducing the recurrences of TRC. Endpoints of studies included visual acuity improvement, inflammatory response, lesion size changes, recurrences of lesions, and adverse effects of medications. Conclusions. There was conflicting evidence as to the effectiveness of systemic antibiotics for TRC. There is no evidence to support that one antibiotic regimen is superior to another so choice needs to be informed by the safety profile. Intravitreous clindamycin with dexamethasone seems to be as effective as systemic treatments. There is currently level I evidence that intermittent trimethoprim-sulfamethoxazole prevents recurrence of the disease.

  18. Genetic diversity of Toxoplasma gondii isolates from Ethiopian feral cats.

    Science.gov (United States)

    Dubey, J P; Choudhary, S; Tilahun, G; Tiao, N; Gebreyes, W A; Zou, X; Su, C

    2013-09-01

    Recent studies indicate greater genetic variability among isolates of Toxoplasma gondii worldwide than previously thought. However, there is no information on genetic diversity of T. gondii from any host in Ethiopia. In the present study, genotyping was performed on viable T. gondii isolates by bioassays in mice from tissues and feces of 27 cats from Ethiopia. Viable T. gondii was isolated from hearts of 26 cats, feces alone of 1 cat, and feces and tissues of 6 cats; in total there were 33 isolates. Genotyping was performed on DNA from cell-cultured derived T. gondii tachyzoites and by using 10 PCR-restriction fragment length polymorphism markers (SAG1, SAG2, SAG3, BTUB, GRA6, c22-8, c29-2, L358, PK1, and Apico). Four genotypes were recognized, including ToxoDB #1 (Type II clonal, nine isolates), ToxoDB #2 (Type III, five isolates), Toxo DB #3 (Type II variant, ten isolates), and ToxoDB #20 (nine isolates). Of interest is the isolation of different genotypes from tissues and feces of two cats, suggesting re-infection or mixed strain T. gondii infection. These findings are of epidemiological significance with respect to shedding of oocysts by cats. This is the first report of genotyping of T. gondii from any host in Ethiopia. Published by Elsevier B.V.

  19. Seroprevalence of Toxoplasma gondii infection in feral cats in Qatar.

    Science.gov (United States)

    Boughattas, Sonia; Behnke, Jerzy; Sharma, Aarti; Abu-Madi, Marawan

    2017-01-18

    Cats are essential in the life cycle of Toxoplasma gondii as they can shed the environmentally resistant oocysts after acquiring infection. Human populations living in cities with high densities of feral cats are therefore likely to be at risk of infection. The current study is the first to estimate the seroprevalence of T. gondii in the feral cat population in Qatar. We investigated the seroprevalence of T. gondii among 495 adult cats from urban and suburban districts in Qatar. Using results from the Modified Agglutination Test, we fitted statistical models with host sex, area and season as explanatory factors and seropositivity as the outcome. The analysis revealed an overall seroprevalence of 82%. Seroprevalence was significantly higher in the summer season (P = 0.006). No significant difference was detected (P > 0.05) between seroprevalence in female and male cats and in cats from urban and suburban districts of Qatar. Despite the seasonal difference, the observed seroprevalence of T. gondii suggests high environmental contamination throughout the year, with some female cats generating more intense responses compared to males. Both findings merit further investigations.

  20. Structure of Toxoplasma gondii fructose-1,6-bisphosphate aldolase

    International Nuclear Information System (INIS)

    Boucher, Lauren E.; Bosch, Jürgen

    2014-01-01

    The structure of T. gondii fructose-1,6-bisphosphate aldolase, a glycolytic enzyme and structural component of the invasion machinery, was determined to a resolution of 2.0 Å. The apicomplexan parasite Toxoplasma gondii must invade host cells to continue its lifecycle. It invades different cell types using an actomyosin motor that is connected to extracellular adhesins via the bridging protein fructose-1,6-@@bisphosphate aldolase. During invasion, aldolase serves in the role of a structural bridging protein, as opposed to its normal enzymatic role in the glycolysis pathway. Crystal structures of the homologous Plasmodium falciparum fructose-1,6-bisphosphate aldolase have been described previously. Here, T. gondii fructose-1,6-bisphosphate aldolase has been crystallized in space group P22 1 2 1 , with the biologically relevant tetramer in the asymmetric unit, and the structure has been determined via molecular replacement to a resolution of 2.0 Å. An analysis of the quality of the model and of the differences between the four chains in the asymmetric unit and a comparison between the T. gondii and P. falciparum aldolase structures is presented

  1. Calcium uptake and proton transport by acidocalcisomes of Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Peter Rohloff

    Full Text Available Acidocalcisomes are acidic calcium stores found in diverse organisms, being conserved from bacteria to humans. They possess an acidic matrix that contains several cations bound to phosphates, which are mainly present in the form of short and long polyphosphate chains. Their matrix is acidified through the action of proton pumps such as a vacuolar proton ATPase and a vacuolar proton pyrophosphatase. Calcium uptake occurs through a Ca(2+/H(+ countertransporting ATPase located in the membrane of the organelle. Acidocalcisomes have been identified in a variety of microorganisms, including Apicomplexan parasites such as Plasmodium and Eimeria species, and in Toxoplasma gondii. We report the purification and characterization of an acidocalcisome fraction from T. gondii tachyzoites after subcellular fractionation and further discontinuous iodixanol gradient purification. Proton and calcium transport activities in the fraction were characterized by fluorescence microscopy and spectrophotometric methods using acridine orange and arsenazo III, respectively. This work will facilitate the understanding of the function of acidocalcisomes in Apicomplexan parasites, as we can now isolate highly purified fractions that could be used for proteomic analysis to find proteins that may clarify the biogenesis of these organelles.

  2. Latent Toxoplasma gondii infection leads to improved action control.

    Science.gov (United States)

    Stock, Ann-Kathrin; Heintschel von Heinegg, Evelyn; Köhling, Hedda-Luise; Beste, Christian

    2014-03-01

    The parasite Toxoplasma gondii has been found to manipulate the behavior of its secondary hosts to increase its own dissemination which is commonly believed to be to the detriment of the host (manipulation hypothesis). The manipulation correlates with an up-regulation of dopaminergic neurotransmission. In humans, different pathologies have been associated with T. gondii infections but most latently infected humans do not seem to display overt impairments. Since a dopamine plus does not necessarily bear exclusively negative consequences in humans, we investigated potential positive consequences of latent toxoplasmosis (and the presumed boosting of dopaminergic neurotransmission) on human cognition and behavior. For this purpose, we focused on action cascading which has been shown to be modulated by dopamine. Based on behavioral and neurophysiological (EEG) data obtained by means of a stop-change paradigm, we were able to demonstrate that healthy young humans can actually benefit from latent T. gondii infection as regards their performance in this task (as indicated by faster response times and a smaller P3 component). The data shows that a latent infection which is assumed to affect the dopaminergic system can lead to paradoxical improvements of cognitive control processes in humans. Copyright © 2013 Elsevier Inc. All rights reserved.

  3. Toxoplasma gondii infection and chronic schizophrenia: is there any association?

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    Salvina Maria de Campos-Carli

    Full Text Available ABSTRACT Background: Toxoplasma gondii (T. gondii infection has been identified as a risk factor for schizophrenia. Objectives: Herein, we sought to evaluate the association between T. gondii infection and clinical symptoms and quality of life in patients with schizophrenia. Methods: We conducted a cross-sectional study with 48 patients with chronic schizophrenia and 40 controls. Peripheral blood was drawn, and IgM and IgG anti-T. gondii antibodies were evaluated by Enzyme-Linked Immunosorbent Assay (ELISA. Depressive, positive and negative symptoms were assessed, respectively, by the Calgary Depression Scale (CDS and the Positive and Negative Syndrome Scale (PANSS. Cognitive performance was assessed in patients by the Brazilian version of the Schizophrenia Cognition Rating Scale (SCoRS-BR. Quality of life was assessed by the Brazilian version of the Quality of Life in Schizophrenia scale (QLS-BR. Results: The prevalence and titers of T. gondii IgM and IgG antibodies did not differ between patients and controls. The positive serology for T. gondii IgG antibodies was not associated with illness symptoms, cognitive performance, depressive symptoms or quality of life. Discussion: Our findings suggest that toxoplasmosis infection is not associated with severity of symptoms, quality of life, cognitive or depressive symptoms in schizophrenia patients.

  4. The Ultrastructural Effects of Sulfachloropyrazine on Toxoplasma Gondii Tachyzoites

    Directory of Open Access Journals (Sweden)

    YB Zeng

    2013-03-01

    Full Text Available Background: Toxoplasmosis is one of the most common parasitic infections of humans and other mammals. This study was aimed to understand the mechanism of action of veterinary medicine-sulfachlo­ropyrazine (SPZ, 99.97% against Toxoplasma gondii.Methods: T. gondii tachyzoites were soaked in PBS (as a control or SPZ (250 mg/mL for 2 h at 37 °C. After being processed, any ultrastructural changes of the tachyzoites that had occurred were observed by Scanning Electron Microscopy (SEM and Transmission Electron Microscopy (TEM.Results: The tachyzoites from control groups with a uniform size had a smooth surface and intact cell or nuclear membranes. In addition, an oval-shaped nucleus, conoids and micronemes were also observed. By contrast, many parasites from the SPZ-treated groups were detrimentally affected by the treatment. Some appeared to be of the vacuolization in their cytoplasm, with the substantial reduc­tion in the number of dense granules and the blur of some organelles.Conclusion: The morphology and ultrastructure of tachyzoites can be affected significantly by SPZ, which might kill the parasite by inhibiting its energy metabolism, inducing apoptosis and damaging its structure. The study provides an experimental basis for further study on the mechanism of SPZ against T. gondii.

  5. Isolation and Genotyping of Toxoplasma gondii in Brazilian Dogs.

    Science.gov (United States)

    da Silva, Jamille Rodrigues; Maciel, Bianca Mendes; de Santana Souza Santos, Luana Karla Nogueira; Carvalho, Fábio Santos; de Santana Rocha, Daniele; Lopes, Carlos Wilson Gomes; Albuquerque, George Rêgo

    2017-06-01

    Strains of Toxoplasma gondii in Brazil are highly genetically diverse compared to strains from North America and Europe. Dogs are epidemiologically important because they act as sentinels for T. gondii infections in humans and are good indicators of environmental contamination. The aim of this study was to isolate and genetically characterize T. gondii strains from tissues of naturally infected Brazilian dogs. For this study, 21 blood samples were collected from dogs at the Zoonosis Control Centers of Ilhéus and Itabuna cities, Bahia, Brazil. The sera were examined for T. gondii antibodies using the indirect hemagglutination test. Brains and hearts of seropositive dogs were bioassayed in mice to isolate and characterize T. gondii parasites by PCR-RFLP using 10 genetic markers (SAG1, newSAG2, SAG3, BTUB, c22-8, c29-2, GRA6, PK1, APICO, and L358). However, T. gondii was isolated from only 4 (57.1%) dogs, designated TgDgBr6, 13, 17, and 21. All strains were virulent, causing clinical changes (rough hair coat, lethargy, and abdominal distention) and the death of all mice within 8-20 days after inoculation. Genetic analysis of these 4 T. gondii isolates revealed 4 distinct genotypes with different clonal lineage combinations (types I, II, and III) and 2 atypical alleles. Using PCR-RFLP with several markers, this study contributes to evaluations of the genetic diversity of strains circulating in Brazil.

  6. Comparative genomics of the Apicomplexan parasites Toxoplasma gondii and Neospora caninum 

    DEFF Research Database (Denmark)

    Reid, Adam James; Vermont, Sarah J.; Cotton, James A.

    2012-01-01

    Coccidian parasites have a major impact on human and animal health world-wide and are among the most successful and widespread parasitic protozoa. They include Neospora caninum which is a leading cause of abortion in cattle and one of its nearest relatives, Toxoplasma gondii. Despite its close...... almost exclusively on molecules which control the interaction of the parasite with the host cell. We show that some secreted invasion-related proteins and surface genes which are known to control virulence and host cell interactions in Toxoplasma are dramatically altered in their expression...... and functionality in Neospora and propose that evolution of these genes may underpin the ecological niches inhabited by coccidian parasites....

  7. Prevalence of Toxoplasma gondii infections in Pennsylvania black bears, Ursus americanus.

    Science.gov (United States)

    Briscoe, N; Humphreys, J G; Dubey, J P

    1993-10-01

    Serum samples from 665 hunter-killed black bears killed in 1989 to 1992 throughout Pennsylvania (USA) were tested for Toxoplasma gondii antibodies by the agglutination test in dilutions of 1:25, 1:50, and 1:500. Toxoplasma gondii antibodies were found in 535 of 665 (80%) bears. Considering the highest dilutions at which antibodies were detected, prevalences were 10% at 1:25, 37% at 1:50 and 33% at 1:500. No significant difference in antibody prevalence was found between males (79%) and females (80%), but a significant difference was found between juvenile (65%) and adult (83%) bears.

  8. Seroprevalence of Toxoplasma gondii in Danish farmed mink (Mustela vison S.)

    DEFF Research Database (Denmark)

    Henriksen, P; Dietz, H. H.; Uttenthal, Åse

    1994-01-01

    One hundred and ninety-five mink sera randomly selected from 17 Danish mink farms were evaluated for the presence of Toxoplasma gondii antibodies in the latex agglutination test. Six (3%) sera contained T. gondii antibodies in titres of 1:64 or more. The estimated 3% prevalence means that 300 000...... mink out of a total mink population of ten million might be infected with Toxoplasma gondii. This large number of possible sero-positive mink in Denmark indicates that there exists a potential risk of acquiring toxoplasmosis by pelting mink....

  9. Prevalence of Toxoplasma gondii in small mammals from the Ardennes region, France.

    Science.gov (United States)

    Afonso, Eve; Poulle, Marie-Lazarine; Lemoine, Mélissa; Villena, Isabelle; Aubert, Dominique; Gilot-Fromont, Emmanuelle

    2007-11-01

    Serum samples from 218 small mammals trapped in forest and grassland in the Ardennes region (North-eastern France) were tested for antibodies to Toxoplasma gondii. Using the modified agglutination test, positive results were found in 4/92 Apodemus sp., 3/64 Clethrionomys glareolus, 0/26 Microtus agrestis, 0/4 Micromys minutus, 3/5 Sorex sp., 2/9 Arvicola terrestris, and 7/18 Talpa europaea. Toxoplasma gondii was not isolated from the heart of seropositive individuals after bioassay in mice. Seroprevalence was significantly higher in large fossorial mammals living in grassland than in small forest mammals, probably related to ecological factors.

  10. AMPK in Pathogens

    OpenAIRE

    Mesquita, Inês Morais; Moreira, Diana; Marques, Belém Sampaio; Laforge, Mireille; Cordeiro-da-Silva, Anabela; Ludovico, Paula; Estaquier, Jérôme; Silvestre, Ricardo Jorge Leal

    2016-01-01

    During host–pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recogn...

  11. Activation of Host IRE1α-Dependent Signaling Axis Contributes the Intracellular Parasitism of Brucella melitensis

    Directory of Open Access Journals (Sweden)

    Aseem Pandey

    2018-04-01

    Full Text Available Brucella spp. are intracellular vacuolar pathogens that causes brucellosis, a worldwide zoonosis of profound importance. We previously demonstrated that the activity of host unfolded protein response (UPR sensor IRE1α (inositol-requiring enzyme 1 and ER-associated autophagy confer susceptibility to Brucella melitensis and Brucella abortus intracellular replication. However, the mechanism by which host IRE1α regulates the pathogen intracellular lifestyle remains elusive. In this study, by employing a diverse array of molecular approaches, including biochemical analyses, fluorescence microscopy imaging, and infection assays using primary cells derived from Ern1 (encoding IRE1 conditional knockout mice, we address this gap in our understanding by demonstrating that a novel IRE1α to ULK1, an important component for autophagy initiation, signaling axis confers susceptibility to Brucella intracellular parasitism. Importantly, deletion or inactivation of key signaling components along this axis, including IRE1α, BAK/BAX, ASK1, and JNK as well as components of the host autophagy system ULK1, Atg9a, and Beclin 1, resulted in striking disruption of Brucella intracellular trafficking and replication. Host kinases in the IRE1α-ULK1 axis, including IRE1α, ASK1, JNK1, and/or AMPKα as well as ULK1, were also coordinately phosphorylated in an IRE1α-dependent fashion upon the pathogen infection. Taken together, our findings demonstrate that the IRE1α-ULK1 signaling axis is subverted by the bacterium to promote intracellular parasitism, and provide new insight into our understanding of the molecular mechanisms of intracellular lifestyle of Brucella.

  12. Glutathione provides a source of cysteine essential for intracellular multiplication of Francisella tularensis.

    Directory of Open Access Journals (Sweden)

    Khaled Alkhuder

    2009-01-01

    Full Text Available Francisella tularensis is a highly infectious bacterium causing the zoonotic disease tularemia. Its ability to multiply and survive in macrophages is critical for its virulence. By screening a bank of HimarFT transposon mutants of the F. tularensis live vaccine strain (LVS to isolate intracellular growth-deficient mutants, we selected one mutant in a gene encoding a putative gamma-glutamyl transpeptidase (GGT. This gene (FTL_0766 was hence designated ggt. The mutant strain showed impaired intracellular multiplication and was strongly attenuated for virulence in mice. Here we present evidence that the GGT activity of F. tularensis allows utilization of glutathione (GSH, gamma-glutamyl-cysteinyl-glycine and gamma-glutamyl-cysteine dipeptide as cysteine sources to ensure intracellular growth. This is the first demonstration of the essential role of a nutrient acquisition system in the intracellular multiplication of F. tularensis. GSH is the most abundant source of cysteine in the host cytosol. Thus, the capacity this intracellular bacterial pathogen has evolved to utilize the available GSH, as a source of cysteine in the host cytosol, constitutes a paradigm of bacteria-host adaptation.

  13. Viral evasion of intracellular DNA and RNA sensing

    Science.gov (United States)

    Chan, Ying Kai; Gack, Michaela U.

    2016-01-01

    The co-evolution of viruses with their hosts has led to the emergence of viral pathogens that are adept at evading or actively suppressing host immunity. Pattern recognition receptors (PRRs) are key components of antiviral immunity that detect conserved molecular features of viral pathogens and initiate signalling that results in the expression of antiviral genes. In this Review, we discuss the strategies that viruses use to escape immune surveillance by key intracellular sensors of viral RNA or DNA, with a focus on RIG-I-like receptors (RLRs), cyclic GMP–AMP synthase (cGAS) and interferon-γ (IFNγ)-inducible protein 16 (IFI16). Such viral strategies include the sequestration or modification of viral nucleic acids, interference with specific post-translational modifications of PRRs or their adaptor proteins, the degradation or cleavage of PRRs or their adaptors, and the sequestration or relocalization of PRRs. An understanding of viral immune-evasion mechanisms at the molecular level may guide the development of vaccines and antivirals. PMID:27174148

  14. Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: implications for infectious disease transmission.

    Directory of Open Access Journals (Sweden)

    Sarah N Bevins

    Full Text Available Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral, that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact, and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV, and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV was not associated with geographic location, while exposure to indirectly transmitted diseases--vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii--varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better

  15. Three pathogens in sympatric populations of pumas, bobcats, and domestic cats: Implications for infections disease transmission

    Science.gov (United States)

    Bevins, Sarah N.; Carver, Scott; Boydston, Erin E.; Lyren, Lisa M.; Alldredge, Mat; Logan, Kenneth A.; Riley, Seth P.D.; Fisher, Robert N.; Vickers, T. Winston; Boyce, Walter; Salman, Mo; Lappin, Michael R.; Crooks, Kevin R.; VandeWoude, Sue

    2012-01-01

    Anthropogenic landscape change can lead to increased opportunities for pathogen transmission between domestic and non-domestic animals. Pumas, bobcats, and domestic cats are sympatric in many areas of North America and share many of the same pathogens, some of which are zoonotic. We analyzed bobcat, puma, and feral domestic cat samples collected from targeted geographic areas. We examined exposure to three pathogens that are taxonomically diverse (bacterial, protozoal, viral), that incorporate multiple transmission strategies (vector-borne, environmental exposure/ingestion, and direct contact), and that vary in species-specificity. Bartonella spp., Feline Immunodeficiency Virus (FIV), and Toxoplasma gondii IgG were detected in all three species with mean respective prevalence as follows: puma 16%, 41% and 75%; bobcat 31%, 22% and 43%; domestic cat 45%, 10% and 1%. Bartonella spp. were highly prevalent among domestic cats in Southern California compared to other cohort groups. Feline Immunodeficiency Virus exposure was primarily associated with species and age, and was not influenced by geographic location. Pumas were more likely to be infected with FIV than bobcats, with domestic cats having the lowest infection rate. Toxoplasma gondii seroprevalence was high in both pumas and bobcats across all sites; in contrast, few domestic cats were seropositive, despite the fact that feral, free ranging domestic cats were targeted in this study. Interestingly, a directly transmitted species-specific disease (FIV) was not associated with geographic location, while exposure to indirectly transmitted diseases – vector-borne for Bartonella spp. and ingestion of oocysts via infected prey or environmental exposure for T. gondii – varied significantly by site. Pathogens transmitted by direct contact may be more dependent upon individual behaviors and intra-specific encounters. Future studies will integrate host density, as well as landscape features, to better

  16. Partial protective effect of intranasal immunization with recombinant Toxoplasma gondii rhoptry protein 17 against toxoplasmosis in mice.

    Directory of Open Access Journals (Sweden)

    Hai-Long Wang

    Full Text Available Toxoplasma gondii (T. gondii is an obligate intracellular protozoan parasite that infects a variety of mammals, including humans. An effective vaccine for this parasite is therefore needed. In this study, RH strain T. gondii rhoptry protein 17 was expressed in bacteria as a fusion with glutathione S-transferase (GST and the recombinant proteins (rTgROP17 were purified via GST-affinity chromatography. BALB/c mice were nasally immunised with rTgROP17, and induction of immune responses and protection against chronic and lethal T. gondii infections were investigated. The results revealed that mice immunised with rTgROP17 produced high levels of specific anti-rTgROP17 IgGs and a mixed IgG1/IgG2a response of IgG2a predominance. The systemic immune response was associated with increased production of Th1 (IFN-γand IL-2 and Th2 (IL-4 cytokines, and enhanced lymphoproliferation (stimulation index, SI in the mice immunised with rTgROP17. Strong mucosal immune responses with increased secretion of TgROP17-specific secretory IgA (SIgA in nasal, vaginal and intestinal washes were also observed in these mice. The vaccinated mice displayed apparent protection against chronic RH strain infection as evidenced by their lower liver and brain parasite burdens (59.17% and 49.08%, respectively than those of the controls. The vaccinated mice also exhibited significant protection against lethal infection of the virulent RH strain (survival increased by 50% compared to the controls. Our data demonstrate that rTgROP17 can trigger strong systemic and mucosal immune responses against T. gondii and that ROP17 is a promising candidate vaccine for toxoplasmosis.

  17. Pathogen exposure varies widely among sympatric populations of wild and domestic felids across the United States.

    Science.gov (United States)

    Carver, Scott; Bevins, Sarah N; Lappin, Michael R; Boydston, Erin E; Lyren, Lisa M; Alldredge, Mathew; Logan, Kenneth A; Sweanor, Linda L; Riley, Seth P D; Serieys, Laurel E K; Fisher, Robert N; Vickers, T Winston; Boyce, Walter; Mcbride, Roy; Cunningham, Mark C; Jennings, Megan; Lewis, Jesse; Lunn, Tamika; Crooks, Kevin R; Vandewoude, Sue

    2016-03-01

    Understanding how landscape, host, and pathogen traits contribute to disease exposure requires systematic evaluations of pathogens within and among host species and geographic regions. The relative importance of these attributes is critical for management of wildlife and mitigating domestic animal and human disease, particularly given rapid ecological changes, such as urbanization. We screened > 1000 samples from sympatric populations of puma (Puma concolor), bobcat (Lynx rufus), and domestic cat (Felis catus) across urban gradients in six sites, representing three regions, in North America for exposure to a representative suite of bacterial, protozoal, and viral pathogens (Bartonella sp., Toxoplasma gondii, feline herpesvirus-1, feline panleukopenea virus, feline calicivirus, and feline immunodeficiency virus). We evaluated prevalence within each species, and examined host trait and land cover determinants of exposure; providing an unprecedented analysis of factors relating to potential for infections in domesticated and wild felids. Prevalence differed among host species (highest for puma and lowest for domestic cat) and was greater for indirectly transmitted pathogens. Sex was inconsistently predictive of exposure to directly transmitted pathogens only, and age infrequently predictive of both direct and indirectly transmitted pathogens. Determinants of pathogen exposure were widely divergent between the wild felid species. For puma, suburban land use predicted increased exposure to Bartonella sp. in southern California, and FHV-1 exposure increased near urban edges in Florida. This may suggest interspecific transmission with domestic cats via flea vectors (California) and direct contact (Florida) around urban boundaries. Bobcats captured near urban areas had increased exposure to T. gondii in Florida, suggesting an urban source of prey Bobcats captured near urban areas in Colorado and Florida had higher FIV exposure, possibly suggesting increased intraspecific

  18. Efficient intracellular delivery and improved biocompatibility of colloidal silver nanoparticles towards intracellular SERS immuno-sensing.

    Science.gov (United States)

    Bhardwaj, Vinay; Srinivasan, Supriya; McGoron, Anthony J

    2015-06-21

    High throughput intracellular delivery strategies, electroporation, passive and TATHA2 facilitated diffusion of colloidal silver nanoparticles (AgNPs) are investigated for cellular toxicity and uptake using state-of-art analytical techniques. The TATHA2 facilitated approach efficiently delivered high payload with no toxicity, pre-requisites for intracellular applications of plasmonic metal nanoparticles (PMNPs) in sensing and therapeutics.

  19. Multiple infections of rodents with zoonotic pathogens in Austria.

    Science.gov (United States)

    Schmidt, Sabrina; Essbauer, Sandra S; Mayer-Scholl, Anne; Poppert, Sven; Schmidt-Chanasit, Jonas; Klempa, Boris; Henning, Klaus; Schares, Gereon; Groschup, Martin H; Spitzenberger, Friederike; Richter, Dania; Heckel, Gerald; Ulrich, Rainer G

    2014-07-01

    Rodents are important reservoirs for a large number of zoonotic pathogens. We examined the occurrence of 11 viral, bacterial, and parasitic agents in rodent populations in Austria, including three different hantaviruses, lymphocytic choriomeningitis virus, orthopox virus, Leptospira spp., Borrelia spp., Rickettsia spp., Bartonella spp., Coxiella burnetii, and Toxoplasma gondii. In 2008, 110 rodents of four species (40 Clethrionomys glareolus, 29 Apodemus flavicollis, 26 Apodemus sylvaticus, and 15 Microtus arvalis) were trapped at two rural sites in Lower Austria. Chest cavity fluid and samples of lung, spleen, kidney, liver, brain, and ear pinna skin were collected. We screened selected tissue samples for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, Leptospira, Borrelia, Rickettsia, Bartonella spp., C. burnetii, and T. gondii by RT-PCR/PCR and detected nucleic acids of Tula hantavirus, Leptospira spp., Borrelia afzelii, Rickettsia spp., and different Bartonella species. Serological investigations were performed for hantaviruses, lymphocytic choriomeningitis virus, orthopox viruses, and Rickettsia spp. Here, Dobrava-Belgrade hantavirus-, Tula hantavirus-, lymphocytic choriomeningitis virus-, orthopox virus-, and rickettsia-specific antibodies were demonstrated. Puumala hantavirus, C. burnetii, and T. gondii were neither detected by RT-PCR/PCR nor by serological methods. In addition, multiple infections with up to three pathogens were shown in nine animals of three rodent species from different trapping sites. In conclusion, these results show that rodents in Austria may host multiple zoonotic pathogens. Our observation raises important questions regarding the interactions of different pathogens in the host, the countermeasures of the host's immune system, the impact of the host-pathogen interaction on the fitness of the host, and the spread of infectious agents among wild rodents and from those to other animals or humans.

  20. COXIELLA BURNETII PATHOGENICITY MOLECULAR BASIS

    Directory of Open Access Journals (Sweden)

    Yu. A. Panferova

    2016-01-01

    Full Text Available Coxiella burnetii is an obligate intracellular gram-negative bacterial pathogen, an ethiological agent of Q-fever, a zoonotic disease, elapsing as an acute (mostly atypical pneumonia or a chronic (mostly endocarditis form. The host range is represented by wide range of mammal, avian and arthropod species, but the main source of human infection are farm animals. The main route of infection is aerosolic. In case of contact with organism pathogen binds with phagocytal monocytic-macrophagal cell line. C. burnetii promotes maturation of specific phagolysosome-like compartment in host cell, called coxiella-containing vacuole, within this vacuole pathogen becames metabolically activated and actively replicates. Coxiella persists as metabolically inactive spore-like form in environment. Internalisation of C. burnetii occurs using actin-mediated phagocytosis and zipper mechanism. After internalization of bacteria maturation of phagolysosome-like compartment and large coxiella-containing vacuole formation occure, and vacuole can occupy nearly the whole cytoplasm of the host cell. Survivance of infected cells is important for chronic infection with C. burnetii. C. burnetii elongate the viability of host cell by two ways: it actively inhibits apoptotic signal cascades and induce pro-survival factors. Exceptthat C. burnetii involves autophagic pathway during coxiella-containing vacuole formation, and induction of autophagy promotes pathogen replication. During infection C. burnetii translocates effector substrates from bacterial cytosole to euca ryotic host cell cytosole using type IV secretion system, where effectors modulate host cell proteins. Overall approximately 130 secreted effectors of type IV transport system, but function of most of them remains unknown to date. Specific sec reted proteins for variety of strains and isolates were identified, confirmed that certain pathotypes of C. burnetii can exist. Identification and

  1. Investigating Internalization and Intracellular Trafficking of GPCRs

    DEFF Research Database (Denmark)

    Foster, Simon R; Bräuner-Osborne, Hans

    2017-01-01

    for signal transduction. One of the major mechanisms for GPCR regulation involves their endocytic trafficking, which serves to internalize the receptors from the plasma membrane and thereby attenuate G protein-dependent signaling. However, there is accumulating evidence to suggest that GPCRs can signal...... independently of G proteins, as well as from intracellular compartments including endosomes. It is in this context that receptor internalization and intracellular trafficking have attracted renewed interest within the GPCR field. In this chapter, we will review the current understanding and methodologies...

  2. Sequence variation in TgROP7 gene among Toxoplasma gondii ...

    African Journals Online (AJOL)

    Yomi

    2012-03-27

    Mar 27, 2012 ... Toxoplasma gondii can infect a wide range of hosts including mammals and birds, causing toxoplasmosis which is one of the most common parasitic zoonoses worldwide. The present study examined sequence variation in rhoptry 7 (ROP7) gene among different T. gondii isolates from different hosts and ...

  3. Sporulation and survival of Toxoplasma gondii oocysts in different types of commercial cat litters

    Science.gov (United States)

    Toxoplasma gondii oocysts are environmentally resistant and can survive outdoors for months in the dry and cold climates. In the present study, sporulation and survival of T. gondii oocysts was studied in different types of cat litters commercially available in the US. Oocysts sporulated within 2-...

  4. Toxoplasmosis in dogs: First report of Toxoplasma gondii infection in any animal species in Angola

    Science.gov (United States)

    Despite the worldwide importance of zoonotic parasite Toxoplasma gondii nothing is known of toxoplasmosis in animals in Angola. The present study aimed at estimating the seroprevalence and also assessing correlates of T. gondii infection in pet dogs from Luanda, Angola. Dogs (n = 103) brought to a v...

  5. High prevalence of Toxoplasma gondii antibodies in dogs in Veracruz, Mexico

    Science.gov (United States)

    Little is known concerning the prevalence of Toxoplasma gondii infection in dogs in Mexico. Here, we investigated antibodies to T. gondii and associated risk factors in 101 dogs from an animal shelter in Veracruz State, Mexico. Canine sera were assayed for T. gondii IgG antibodies by using the modif...

  6. Uptake and transmission of Toxoplasma gondii oocysts by migratory filter-feeding fish

    Science.gov (United States)

    Toxoplasma gondii is a ubiquitous parasitic protozoan known to cause disease and death in warm-blooded animals. Bottlenose dolphins, walruses, sea otters, and other marine animals worldwide have died from toxoplasmosis, but the source of this parasite in the marine environment h...

  7. Low Seroprevalence of Leishmania infantum and Toxoplasma gondii in the Horse Population in Israel

    NARCIS (Netherlands)

    Aharonson-Raz, Karin; Baneth, Gad; Lopes, Ana Patrícia; Brancal, Hugo; Schallig, Henk; Cardoso, Luís; Steinman, Amir

    2015-01-01

    A cross-sectional investigation was done on the seroprevalence of Leishmania infantum and Toxoplasma gondii infection among apparently healthy horses in Israel. This survey included 383 horses distributed in 22 farms throughout Israel during the years 2011-2013. Serum samples were tested for the

  8. Toxoplasma gondii in stranded marine mammals from the North Sea and Eastern Atlantic Ocean

    NARCIS (Netherlands)

    Velde, van de Norbert; Devleesschauwer, Brecht; Leopold, Mardik; Begeman, Lineke; IJsseldijk, Lonneke; Hiemstra, Sjoukje; IJzer, Jooske; Brownlow, Andrew; Davison, Nicholas; Haelters, Jan

    2016-01-01

    The occurrence of the zoonotic protozoan parasite Toxoplasma gondii in marine mammals remains a poorly understood phenomenon. In this study, samples from 589 marine mammal species and 34 European otters (Lutra lutra), stranded on the coasts of Scotland, Belgium, France, The Netherlands and

  9. PREVALENCE OF ANTIBODIES AGAINST TOXOPLASMA GONDII IN POLAR BEARS (URSUS MARITIMUS) FROM SVALBARD AND EAST GREENLAND

    Science.gov (United States)

    Serum samples from 419 polar bears (Ursus maritimus) from Svalbard and the Barents Sea (collected 1990 - 2000) and 108 polar bears from East Greenland (collected 1999 - 2004) were assayed for antibodies against Toxoplasma gondii using the modified agglutination test (MAT). Antibody prevalences were ...

  10. Inactivation of Toxoplasma gondii on blueberries using low dose irradiation without affecting quality

    Science.gov (United States)

    Toxoplasma gondii is a common protozoan parasite, whose environmentally-resistant stage, the oocyst, can contaminate irrigation water and fresh edible produce. Current washing steps in produce processing may not be effective for eliminating T. gondii from at-risk varieties of produce. The objective ...

  11. Molecular diagnosis of toxoplasmosis: value of the buffy coat for the detection of circulating Toxoplasma gondii.

    Science.gov (United States)

    Brenier-Pinchart, Marie-Pierre; Capderou, Elodie; Bertini, Rose-Laurence; Bailly, Sébastien; Fricker-Hidalgo, Hélène; Varlet-Marie, Emmanuelle; Murat, Jean-Benjamin; Sterkers, Yvon; Touafek, Fériel; Bastien, Patrick; Pelloux, Hervé

    2015-08-01

    Early detection of Toxoplasma tachyzoites circulating in blood using PCR is recommended for immunosuppressed patients at high risk for disseminated toxoplasmosis. Using a toxoplasmosis mouse model, we show that the sensitivity of detection is higher using buffy coat isolated from a large blood volume than using whole blood for this molecular monitoring. Copyright © 2015 Elsevier Inc. All rights reserved.

  12. Effectiveness of health education on Toxoplasma-related knowledge, behaviour, and risk of seroconversion in pregnancy.

    Science.gov (United States)

    Gollub, Erica L; Leroy, Valériane; Gilbert, Ruth; Chêne, Geneviève; Wallon, Martine

    2008-02-01

    We conducted a bibliographic literature search using MEDLINE to review the effectiveness of health education on Toxoplasma-related knowledge, behaviour, and risk of seroconversion in pregnant women. We pre-selected studies that used comparative study designs (randomized clinical trial, quasi-experimental design or historical control), that were conducted among pregnant women, and which employed specific, Toxoplasma-related outcome measures: knowledge, behaviour, or Toxoplasma infection rate. Four studies met the inclusion criteria. All had serious methodological flaws. A Belgian study reported a significant decrease in the incidence of Toxoplasma seroconversion after the introduction of intensive counselling for pregnant women about toxoplasmosis. In Poland, a significant increase in knowledge was observed after a multi-pronged, public health educational program was launched. In Canada, an increase in knowledge and prevention behaviours was reported in the intervention group receiving counselling by trained facilitators compared with the control group. In France, no significant changes in risk behaviour were observed following a physician-delivered intervention. This review highlights the weakness of the literature in the area and the lack of studies measuring actual seroconversion. There is suggestive evidence that health education approaches may help reduce risk of congenital toxoplasmosis but this problem requires further study using more rigorous research design and methodology.

  13. Seroprevalence of Toxoplasma gondii in American Black Bears ( Ursus americanus ) of the Central Appalachians, USA.

    Science.gov (United States)

    Cox, John J; Murphy, Sean M; Augustine, Ben C; Guthrie, Joseph M; Hast, John T; Maehr, Sutton C; McDermott, Joseph

    2017-07-01

    We assessed Toxoplasma gondii seroprevalence in 53 free-ranging American black bears ( Ursus americanus ) in the Central Appalachian Mountains, US. Seroprevalence was 62% with no difference between males and females or between juvenile and adult bears. Wildlife agencies should consider warnings in hunter education programs to reduce the chances for human infection from this source.

  14. Behavioural and biochemical profiles in rats infected with Toxoplasma gondii or lipopolysaccharide: animal models of schizophrenia

    Czech Academy of Sciences Publication Activity Database

    Tejkalová, H.; Kodym, P.; Kačer, P.; Klaschka, Jan; Horáček, J.

    2013-01-01

    Roč. 24, e-Suppl. 1 (2013), e22 ISSN 0955-8810. [Biennal meeting of the EBPS /15./. 06.09.2013-09.09.2013, La Rochelle] Institutional support: RVO:67985807 Keywords : animal models * schizophrenia * behaviour * LPS * Toxoplasma gondii Subject RIV: FH - Neurology

  15. The first isolation and molecular characterization of Toxoplasma gondii from horses in Serbia.

    NARCIS (Netherlands)

    Klun, Ivana; Uzelac, Aleksandra; Villena, Isabelle; Mercier, Aurélien; Bobić, Branko; Nikolić, Aleksandra; Rajnpreht, Irena; Opsteegh, Marieke; Aubert, Dominique; Blaga, Radu; van der Giessen, Joke; Djurković-Djaković, Olgica

    2017-01-01

    Consumption of undercooked or insufficiently cured meat is a major risk factor for human infection with Toxoplasma gondii. Although horsemeat is typically consumed rare or undercooked, information on the risk of T. gondii from infected horse meat to humans is scarce. Here, we present the results of

  16. Prevalence of antibodies to Leishmania infantum and Toxoplasma gondii in horses from the north of Portugal

    Science.gov (United States)

    Background Leishmania infantum and Toxoplasma gondii are protozoa with zoonotic and economic importance. Prevalences of antibodies to these agents were assessed in 173 horses from the north of Portugal. Findings Antibodies to L. infantum were detected by the direct agglutination test (DAT); seven (...

  17. Isolation of viable Toxoplasma gondii, molecular characterization, and seroprevalence in elk (Cervus canadensis) in Pennsylvania, USA

    Science.gov (United States)

    Toxoplasmosis is a worldwide zoonosis. The ingestion of uncooked/undercooked meat and consumption of water contaminated with Toxoplasma gondii oocysts excreted by felids are the main modes of transmission of this parasite. Thousands of wild cervids are hunted or killed in traffic accidents yearly bu...

  18. Seroepidemiology of Toxoplasma gondii infection in bats from São Paulo city, Brazil

    Science.gov (United States)

    Toxoplasmosis is a parasitic zoonosis caused by Toxoplasma gondii with a worldwide distribution. The aim of this study was to determine the frequency of IgG anti-T. gondii antibodies in bats from São Paulo city, Brazil. A total of 616 serum samples were collected from 22 species of bats. Anti-T. gon...

  19. Use of filter papers to determine seroprevalence of Toxoplasma gondii among hunted ungulates

    Science.gov (United States)

    Toxoplasmosis is a zoonosis caused by the protozoan Toxoplasma gondii, and it is found worldwide. To determine whether ungulates are reservoirs of T. gondii in an isolated and remote region of the northeastern Peruvian Amazon, antibodies to T. gondii were determined in 5 species of ungulates by the...

  20. Cats and Goat Whey Associated with Toxoplasma gondii Infection in Pigs

    NARCIS (Netherlands)

    Meerburg, B.G.; Riel, van J.W.; Cornelissen, J.B.W.J.; Kijlstra, A.; Mul, M.F.

    2006-01-01

    In organic livestock production systems, farm-management factors are thought to play an important role in the on-farm prevalence of Toxoplasma gondii. Serological results and the results of an HACCP analysis were combined to determine important risk factors for the prevalence of this protozoan

  1. Prevalence of antibodies to Leishmania infantum and Toxoplasma gondii in horses from the north of Portugal

    NARCIS (Netherlands)

    Lopes, Ana Patrícia; Sousa, Susana; Dubey, Jp; Ribeiro, Ana J.; Silvestre, Ricardo; Cotovio, Mário; Schallig, Henk Dfh; Cardoso, Luís; Cordeiro-da-Silva, Anabela

    2013-01-01

    Leishmania infantum and Toxoplasma gondii are protozoa with zoonotic and economic importance. Prevalences of antibodies to these agents were assessed in 173 horses from the north of Portugal. Antibodies to L. infantum were detected by the direct agglutination test (DAT); seven (4.0%) horses were

  2. Serotyping of Toxoplasma gondii in Cats (Felis domesticus) Reveals Predominance of Type II Infections in Germany

    Science.gov (United States)

    Background: Cats are definitive hosts of Toxoplasma gondii and play an essential role in the epidemiology of this parasite. The study aims at clarifying whether cats are able to develop specific antibodies against different clonal types of T. gondii and to determine by serotyping the T. gondii clona...

  3. Antibodies to Toxoplasma gondii and Leishmania spp. in domestic cats from Luanda, Angola

    Science.gov (United States)

    Toxoplasma gondii and Leishmania spp. are zoonotic agents of importance to public health, with domestic cats as potential reservoirs for both protozoal infections. The present study aimed at assessing for the first time the seroprevalence of these zoonotic parasites in a domestic feline population l...

  4. Isolation and genetic characterization of Toxoplasma gondii from the gray wolf Canis lupus

    Science.gov (United States)

    Little is known of the genetic diversity of Toxoplasma gondii circulating in wildlife. In the present study feral gray wolf (Canis lupus) from Minnesota were examined for T. gondii infection. Antibodies to T. gondii were detected in 130 (52.4%) of 248 wolves tested by the modified agglutination test...

  5. Macrophages facilitate the excystation and differentiation of Toxoplasma gondii sporozoites into tachyzoites following oocyst internalization

    Science.gov (United States)

    Toxoplasma gondii is a common parasite of humans and domestic animals, which is transmitted via oocysts in cat faeces or tissue cysts in contaminated meat. The oocyst and sporocyst walls are multilayered polymeric structures that protect the infective sporozoites from deleterious physical and chemic...

  6. Prevalence of Toxoplasma gondii IgG and IgM and associated risk ...

    African Journals Online (AJOL)

    Prevalence of Toxoplasma gondii IgG and IgM and associated risk factors among HIV-positive and HIV-negative patients in Vhembe district of South Africa. ... shown a high prevalence of T. gondii (IgG) among patients attending different HIV clinics in the Vhembe district with no current infections among pregnant women.

  7. Transplacental transmission of Toxoplasma gondii in minipigs infected with strains of different virulence

    DEFF Research Database (Denmark)

    Jungersen, Gregers; Bille-Hansen, Vivi; Jensen, Lene Bai

    2001-01-01

    Infections with the Zoonotic protozoan Toxoplasma gondii during pregnancy can result in severe fetal infections. To investigate the use of pigs as animal models for congenital toxoplasmosis, tachyzoites of 5 T. gondii strains, with low to intermediate virulence in mice, were intravenously...... animal models fur studies of transplacental transmission and pathogenesis of congenital toxoplasmosis....

  8. Toxoplasma gondii seroprevalence in free-ranging moose (Alces alces) hunted for human consumption in Estonia

    DEFF Research Database (Denmark)

    Remes, Noora; Kärssin, Age; Must, Kärt

    2018-01-01

    In Estonia, northeastern Europe, antibodies against Toxoplasma gondii are common in many host species, including wildlife, domestic animals, and humans. Our nationwide study aimed to estimate T. gondii seroprevalence and its geographical distribution, and to evaluate plausible risk factors for se...

  9. Seroprevalence and risk factors for Toxoplasma gondii infection in domestic cats in The Netherlands

    NARCIS (Netherlands)

    Opsteegh, M.; Haveman, R.; Swart, A.; Mensink-Beerepoot, M.E.; Hofhuis, A.; Langelaar, M.F.M.; van der Giessen, J.W.B.

    2012-01-01

    Cats, as definitive hosts, play an important role in the transmission of Toxoplasma gondii. To determine the seroprevalence and risk factors for T. gondii infection in Dutch domestic cats, serum samples of 450 cats were tested for T. gondii antibodies by indirect ELISA. Binary mixture analysis was

  10. An experimental Toxoplasma gondii dose response challenge model to study therapeutic or vaccine efficacy in cats

    NARCIS (Netherlands)

    Cornelissen, J.B.W.J.; Giessen, van der J.W.B.; Takumi, K.; Teunis, P.F.M.; Wisselink, H.J.

    2014-01-01

    High numbers of Toxoplasma gondii oocysts in the environment are a risk factor to humans. The environmental contamination might be reduced by vaccinating the definitive host, cats. An experimental challenge model is necessary to quantitatively assess the efficacy of a vaccine or drug treatment.

  11. Toxoplasma gondii in women with bad obstetric history and infertility: a five-year study

    Directory of Open Access Journals (Sweden)

    Abida Malik

    2014-02-01

    Full Text Available Objective: To evaluate the role of Toxoplasma gondii in women with bad obstetric (BOH history and in women with primary and secondary infertility. Methods: This study was conducted in the Department of Microbiology, Jawaharlal Nehru Medical College and Hospital for a period of 5 years from January 2004 to December 2009. Quantitative determination of IgM antibodies to Toxoplasma gondii infection was done by IgM capture ELISA in patients with history of BOH or infertility. Results: Out of a total of 441 subjects included in the study, 417 (94.6% had a BOH and 24 (5.4% subjects had infertility. Toxoplasma was found to be more common in females with two or more abortions 52 (76.5%. Similarly in patients with infertility due to Toxoplasma, secondary infertility (66.7% was more common than primary infertility. About 40.3% patients with BOH and 20% patients with infertility had healthy live issues after treatment with spiramycin. Conclusions: Toxoplasmosis is thus, an easily treatable cause of abortions and infertility. All antenatal females and females with infertility should be screened for toxoplasmosis.

  12. Seroprevalence and isolation of viable Toxoplasma gondii from raptors in the southeastern USA

    Science.gov (United States)

    Raptors are good indicators of the prevalence of Toxoplasma gondii in the environment because they prey on small mammals and birds. These prey species are a major source of infection in felids, which shed the environmentally resistant oocysts. We assessed T. gondii infection in 281 opportunistically...

  13. Antibodies to Toxoplasma gondii and Leishmania spp. in domestic cats from Luanda, Angola

    NARCIS (Netherlands)

    Lopes, Ana Patrícia; Oliveira, Ana Cristina; Granada, Sara; Rodrigues, Filipa T.; Papadopoulos, Elias; Schallig, Henk; Dubey, Jitender P.; Cardoso, Luís

    2017-01-01

    Toxoplasma gondii and Leishmania spp. are zoonotic protozoa of importance to animal and public health. The present study aimed to assess for the first time the seroprevalence of these zoonotic parasites in a domestic feline population living in Luanda, Angola. One hundred and two cats were sampled

  14. Isolation of Viable Toxoplasma gondii from Tissues and Feces of Cats from Addis Ababa, Ethiopia

    Science.gov (United States)

    Cats are important in the epidemiology of Toxoplasma gondii because they are the only hosts that excrete environmentally resistant oocysts in feces. In the present study, hearts, serum, and feces from 36 feral cats from Addis Ababa area, Ethiopia were examined for T. gondii infection. Antibodies to ...

  15. Serology and genetics of Toxoplasma gondii in endangered Hawaiian (Nene) geese (Branta sandvicensis)

    Science.gov (United States)

    Toxoplasma gondii is parasite transmitted by feral cats that has historically caused mortality in native Hawaiian birds. A recent study revealed that this parasite accounts for ca. 4% of causes of mortality in native Hawaiian geese (nene-Branta sandvicensis). To know how widespread exposure to the...

  16. Toxoplasma gondii antibodies in domiciled cats from rio branco Municipality, Acre State, Brazil

    Directory of Open Access Journals (Sweden)

    Soraia Figueiredo de Souza

    2015-12-01

    Full Text Available Blood samples were collected from 89 cats to assess the prevalence of IgG antibodies against Toxoplasma gondii by indirect immunofluorescence (IIF and the possible risk factors associated with feline Toxoplasma gondii infection. An epidemiological questionnaire was developed and implemented for owners of domestic cats domiciled in Rio Branco, Acre. The results were statistically evaluated with the odds ratio and chi-square tests, considering the significance level of 5%. Of 89 animals’ samples, 22 had antibodies against Toxoplasma gondii. Among the 22 reactive animals, 15 (68.19% were female, 15 (68.19% were less than one year old and 20 (90% were cross breed. Concerning risk factors, there was no difference (p > 0.05 between the variables evaluated by the chi-square test. Moreover, 16 (72% cats were fed a mixed diet, 20 (90% of the cats had hunting habits, 18 (81% had contact with animals of another species, 11 (50% had access to the street, and 22 (95% lived in homes that had areas of grass or dirt. In conclusion, the prevalence of anti-Toxoplasma gondii in domestic cats was 22.7%, and there were no significant risk factors for feline toxoplasmosis in the municipality of Rio Branco, Acre.

  17. Spatial epidemiology of Toxoplasma gondii infection in goats in Serbia

    Directory of Open Access Journals (Sweden)

    Vitomir Djokić

    2014-05-01

    Full Text Available A major risk factor for Toxoplasma gondii infection is consumption of undercooked meat. Increasing demand for goat meat is likely to promote the role of this animal for human toxoplasmosis. As there are virtually no data on toxoplasmosis in goats in Serbia, we undertook a cross-sectional serological study, including prediction modelling using geographical information systems (GIS. Sera from 431 goats reared in 143 households/farms throughout Serbia, sampled between January 2010 and September 2011, were examined for T. gondii antibodies by a modified agglutination test. Seroprevalence was 73.3% at the individual level and 84.6% at the farm level. Risk factor analysis showed above two-fold higher risk of infection for goats used for all purposes compared to dairy goats (P = 0.012, almost seven-fold higher risk for goats kept as sole species versus those kept with other animals (P = 0.001 and a two-fold lower risk for goats introduced from outside the farm compared to those raised on the farm (P = 0.027. Moreover, households/farms located in centre-eastern Serbia were found to be less often infected than those in northern Serbia (P = 0.004. The risk factor analysis was fully supported by spatial analysis based on a GIS database containing data on origin, serology, land cover, elevation, meteorology and a spatial prediction map based on kriging analysis, which showed western Serbia as the area most likely for finding goats positive for T. gondii and centre-eastern Serbia as the least likely. In addition, rainfall favoured seropositivity, whereas temperature, humidity and elevation did not.

  18. Neospora caninum and Toxoplasma gondii antibody prevalence in Alaska wildlife.

    Science.gov (United States)

    Stieve, Erica; Beckmen, Kimberlee; Kania, Stephen A; Widner, Amanda; Patton, Sharon

    2010-04-01

    Free-ranging caribou and moose populations in some regions of Alaska undergo periodic declines in numbers. Caribou and moose are managed by the state as valuable resources for not only sustenance and subsistence, but also for cultural heritage. Incidence and prevalence of diseases that may impact herd health and recruitment from year to year are relevant to management decisions aimed to protect the long-term viability of these herds. Neospora caninum and Toxoplasma gondii are two apicomplexan parasites that can cause neurologic disease and abortions in their intermediate hosts and less frequently cause disease in their definitive hosts. The definitive hosts of N. caninum and T. gondii are canids and felids, respectively, and prevalence in the environment is in part dependent on maintenance of the life cycle through the definitive hosts. Serum samples from caribou (Rangifer tarandus, n=453), wolf (Canis lupus, n=324), moose (Alces alces, n=201), black-tailed deer (Odocoileus hemionus, n=55), coyote (Canis latrans, n=12), and fox (Vulpes vulpes, n=9) collected in Alaska were assayed for N. caninum- and T. gondii-reactive antibodies with an immunofluorescent antibody test (IFAT) and a modified agglutination test (MAT), respectively. Seroprevalence of N. caninum was greater in caribou (11.5%) than in wolves (9.0%), moose (0.5%), or black-tailed deer (0%). Seroprevalence of T. gondii was greater in wolves (17.8%) than in caribou (0.4%), moose (0%), or black-tailed deer (0%). Seroprevalence of N. caninum and T. gondii were 16.7% and 0.0% in coyotes and 0.0% and 12.5% in fox, but small sample sizes prevented further analysis. Antibodies to N. caninum in young caribou compared to adult caribou suggest that vertical transmission may be an important component of new infections in Alaskan caribou. The spatial distribution of antibody-positive individuals across Alaska may reflect differences in frequency of definitive hosts and alteration of predation patterns among regions.

  19. Differential Roles for Inner Membrane Complex Proteins across Toxoplasma gondii and Sarcocystis neurona Development.

    Science.gov (United States)

    Dubey, Rashmi; Harrison, Brooke; Dangoudoubiyam, Sriveny; Bandini, Giulia; Cheng, Katherine; Kosber, Aziz; Agop-Nersesian, Carolina; Howe, Daniel K; Samuelson, John; Ferguson, David J P; Gubbels, Marc-Jan

    2017-01-01

    The inner membrane complex (IMC) of apicomplexan parasites contains a network of intermediate filament-like proteins. The 14 alveolin domain-containing IMC proteins in Toxoplasma gondii fall into different groups defined by their distinct spatiotemporal dynamics during the internal budding process of tachyzoites. Here, we analyzed representatives of different IMC protein groups across all stages of the Toxoplasma life cycle and during Sarcocystis neurona asexual development. We found that across asexually dividing Toxoplasma stages, IMC7 is present exclusively in the mother's cytoskeleton, whereas IMC1 and IMC3 are both present in mother and daughter cytoskeletons (IMC3 is strongly enriched in daughter buds). In developing macro- and microgametocytes, IMC1 and -3 are absent, whereas IMC7 is lost in early microgametocytes but retained in macrogametocytes until late in their development. We found no roles for IMC proteins during meiosis and sporoblast formation. However, we observed that IMC1 and IMC3, but not IMC7, are present in sporozoites. Although the spatiotemporal pattern of IMC15 and IMC3 suggests orthologous functions in Sarcocystis , IMC7 may have functionally diverged in Sarcocystis merozoites. To functionally characterize IMC proteins, we knocked out IMC7, -12, -14, and -15 in Toxoplasma . IMC14 and -15 appear to be involved in switching between endodyogeny and endopolygeny. In addition, IMC7, -12, and -14, which are all recruited to the cytoskeleton outside cytokinesis, are critical for the structural integrity of extracellular tachyzoites. Altogether, stage- and development-specific roles for IMC proteins can be discerned, suggesting different niches for each IMC protein across the entire life cycle. IMPORTANCE The inner membrane complex (IMC) is a defining feature of apicomplexan parasites key to both their motility and unique cell division. To provide further insights into the IMC, we analyzed the dynamics and functions of representative alveolin

  20. High prevalence of anti-toxoplasma antibodies and absence of Toxoplasma gondii infection risk factors among pregnant women attending routine antenatal care in two Hospitals of Addis Ababa, Ethiopia

    Directory of Open Access Journals (Sweden)

    Woyneshet Gelaye

    2015-05-01

    Conclusion: Prevalence of toxoplasmosis among pregnant women in Addis Ababa, Ethiopia is higher than that reported from other countries. Efforts to describe risk factors for toxoplasma infection among Ethiopians should focus in children.

  1. Toxoplasma gondii seroprevalence in pet cats in Norway and risk factors for seropositivity.

    Science.gov (United States)

    Sævik, Bente Kristin; Krontveit, Randi Ingebjørg; Eggen, Kristine P; Malmberg, Nina; Thoresen, Stein I; Prestrud, Kristin W

    2015-12-01

    The aims of the study were to estimate Toxoplasma gondii seroprevalence in pet cats in Norway and to evaluate risk factors for seropositivity. Additionally, serum biochemistry and haematological variables for T gondii seropositive and seronegative cats were compared. A convenience sample of surplus sera submitted to the Central Laboratory, Norwegian University of Life Sciences, was collected. The samples were from healthy cats and cats with a variety of diseases. Analyses for IgG antibodies to T gondii were performed with a commercial direct agglutination test, with 1:40 as the threshold value. For risk factor analysis a logistic regression model of the relationship between predictors and the outcome was applied. One hundred and ninety-six of 478 cats were seropositive for T gondii, and the estimated seroprevalence in the study sample was 41.0% (95% confidence interval 36.6-45.4). Compared with domestic cats, pedigree cats had reduced risk for Toxoplasma seropositivity (odds ratio [OR] 0.42). Males had increased risk (OR 1.63) compared with females. The effect of age was highly significant, and an increase in the cats' age across the interquartile range (IQR; 52-160 months/4-13 years of age) doubled the risk of Toxoplasma seropositivity (OR 2.11). The risk for Toxoplasma seropositivity among cats living in Oslo was significantly reduced (OR 0.51) when compared with the rest of Norway. Pet cats in Norway appear to be commonly exposed to T gondii. Signalment and geographical region influenced the odds of Toxoplasma seropositivity, whereas health status did not. © ISFM and AAFP 2015.

  2. Determination of Antibodies (IgG, IgM against Toxoplasma gondii in Patients with Cancer

    Directory of Open Access Journals (Sweden)

    M Pedram

    2007-08-01

    Full Text Available Background: The aim of this study was determination of antibodies (IgG, IgM against Toxoplasma in malignant patients in order to refer the patients on time to the physician for treatment.Methods: This study was carried out on 252 malignant patients and 252 healthy normal subjects (as control obtained from Shafa Hospital and Medical Diagnostic Laboratory (Iran-Zamin, in Ahwaz city. Patient's information was recorded in a questionnaire before sampling. Serum samples of patients were examined for IgG and IgM antibodies by ELISA technique using Trinity kits. Results: The results of this study revealed the presence of Toxoplasma antibodies in 114 (45.2% cases of patients who were positive for Toxoplasma IgG antibodies, and 26 (10.3% cases were confirmed to be positive for Toxoplasma IgM antibodies and also 17 (6.7% of cases had both IgG and IgM antibodies against Toxoplasma gondii. In control group 92 (36.5% cases and 15 (6% cases revealed seropositive for IgG and IgM antibodies, respectively. There were no significant differences between sex, close contact with cat, living region, chemotherapy, and seropositivity rate of toxoplasmosis in patients. Comparing the age groups, the highest seropositive rate showed in the age of 51 years or higher, and their rates had tendency to increase with age in both groups. No seropositivity significant relationship was found between patients and control group.Conclusion: According to the prevalence of positive cases in these patients, it is necessary to examine the patients for toxoplasmosis before, during and after chemotherapy.

  3. THE ROLE OF HORMONES ON Toxoplasma gondii INFECTION: A SYSTEMATIC REVIEW

    Directory of Open Access Journals (Sweden)

    María De La Luz Galván-Ramírez

    2014-10-01

    Full Text Available Background: Toxoplasma gondii is the causal agent of toxoplasmosis in which one third of the world’s population has been infected. In pregnant women, it may cause abortion and severe damage to the fetal central nervous system. During pregnancy, the prevalence of toxoplasmosis increases throughout the second and third quarter of gestation, simultaneously progesterone and 17β-estradiol also increase. Thus, it has been suggested that these hormones can aggravate or reduce parasite reproduction. The aim of this study was reviewing the relationship between hormones and infection caused by T. gondii in several experimental animal models and humans, focused mainly on: a congenital transmission, b parasite reproduction, c strain virulence, d levels of hormone in host induced by T. gondii infection and e participation of hormone receptors in Toxoplasma gondii infection.Are the hormones specific modulators of T. gondii infection?A systematic review methodology was used to consult several databases (Pub Med, Lilacs, Medline, Science direct, Scielo, Ebsco, Sprinker, Wiley and Google Scholar dated from September, 2013 to March, 2014. Results: 30 studies were included; eight studies in humans and 22 in animals and cell cultures. In the human studies, the most studied hormones were testosterone, progesterone, prolactin and 17-ß estradiol. Type I (RH and BK and Type II (Prugniaud, SC, ME49,T45, P78 and T38 were the most frequent experimental strains. Conclusions: Thirty-five years have passed since the first studies regarding Toxoplasma gondii infection and its relationship with hormones. This systematic review suggests that hormones modulate Toxoplasma gondii infection in different animal models. However, given that data were not comparable, further studies are required to determine the mechanism of hormone action in the Toxoplasma gondii infectious process.

  4. Cationic polymers for intracellular delivery of proteins

    NARCIS (Netherlands)

    Coué, G.M.J.P.C.; Engbersen, Johannes F.J.; Samal, Sangram; Dubruel, Peter

    2015-01-01

    Many therapeutic proteins exert their pharmaceutical action inside the cytoplasm or onto individual organelles inside the cell. Intracellular protein delivery is considered to be the most direct, fastest and safest approach for curing gene-deficiency diseases, enhancing vaccination and triggering

  5. Molecular detection and characterization of sustainable intracellular ...

    African Journals Online (AJOL)

    3Centre for Biopolymer and Bio-Molecular Research, Athlone College of Technology, Republic of Ireland. ... cells was associated with the elongation of micro-villar extension that ... Keywords: Intracellular contaminants, cell cultures, bacteria culture, pre-clinical studies. ... production work involving culture technology.

  6. Spatial Cytoskeleton Organization Supports Targeted Intracellular Transport

    Science.gov (United States)

    Hafner, Anne E.; Rieger, Heiko

    2018-03-01

    The efficiency of intracellular cargo transport from specific source to target locations is strongly dependent upon molecular motor-assisted motion along the cytoskeleton. Radial transport along microtubules and lateral transport along the filaments of the actin cortex underneath the cell membrane are characteristic for cells with a centrosome. The interplay between the specific cytoskeleton organization and the motor performance realizes a spatially inhomogeneous intermittent search strategy. In order to analyze the efficiency of such intracellular search strategies we formulate a random velocity model with intermittent arrest states. We evaluate efficiency in terms of mean first passage times for three different, frequently encountered intracellular transport tasks: i) the narrow escape problem, which emerges during cargo transport to a synapse or other specific region of the cell membrane, ii) the reaction problem, which considers the binding time of two particles within the cell, and iii) the reaction-escape problem, which arises when cargo must be released at a synapse only after pairing with another particle. Our results indicate that cells are able to realize efficient search strategies for various intracellular transport tasks economically through a spatial cytoskeleton organization that involves only a narrow actin cortex rather than a cell body filled with randomly oriented actin filaments.

  7. Biological synthesis and characterization of intracellular gold ...

    Indian Academy of Sciences (India)

    In the present study, Aspergillus fumigatus was used for the intracellular synthesis of gold nanoparticles. Stable nanoparticles were produced when an aqueous solution of chloroauric acid (HAuCl4) was reduced by A. fumigatus biomass as the reducing agent. Production of nanoparticles was confirmed by the colour ...

  8. Fundamental Roles of the Golgi-Associated Toxoplasma Aspartyl Protease, ASP5, at the Host-Parasite Interface

    Czech Academy of Sciences Publication Activity Database

    Hammoudi, P.-M.; Jacot, D.; Mueller, C.; Di Cristina, M.; Dogga, S.K.; Marq, J.-B.; Romano, J.; Tosetti, N.; Dubrot, J.; Emre, Y.; Lunghi, M.; Coppens, I.; Yamamoto, M.; Sojka, Daniel; Pino, P.; Soldati-Favre, D.

    2015-01-01

    Roč. 11, č. 10 (2015), e1005211 E-ISSN 1553-7374 Institutional support: RVO:60077344 Keywords : Toxoplasma gondii * Plasmodium proteins * ASP5 Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 7.003, year: 2015

  9. Molecular Detection of Toxoplasma gondii Oocytes in the Soil from the Public Parks of the Arak City, Iran

    Directory of Open Access Journals (Sweden)

    Hadis Solymane

    2014-02-01

    Conclusion: This study showed soils of public parks in the Arak city were contaminated to oocyst of Toxoplasma. Also molecular method for the detection of parasites in the soil was more suitable than staining method.

  10. Porphyromonas gingivalis evasion of autophagy and intracellular killing by human myeloid dendritic cells involves DC-SIGN-TLR2 crosstalk.

    Science.gov (United States)

    El-Awady, Ahmed R; Miles, Brodie; Scisci, Elizabeth; Kurago, Zoya B; Palani, Chithra D; Arce, Roger M; Waller, Jennifer L; Genco, Caroline A; Slocum, Connie; Manning, Matthew; Schoenlein, Patricia V; Cutler, Christopher W

    2015-02-01

    Signaling via pattern recognition receptors (PRRs) expressed on professional antigen presenting cells, such as dendritic cells (DCs), is crucial to the fate of engulfed microbes. Among the many PRRs expressed by DCs are Toll-like receptors (TLRs) and C-type lectins such as DC-SIGN. DC-SIGN is targeted by several major human pathogens for immune-evasion, although its role in intracellular routing of pathogens to autophagosomes is poorly understood. Here we examined the role of DC-SIGN and TLRs in evasion of autophagy and survival of Porphyromonas gingivalis in human monocyte-derived DCs (MoDCs). We employed a panel of P. gingivalis isogenic fimbriae deficient strains with defined defects in Mfa-1 fimbriae, a DC-SIGN ligand, and FimA fimbriae, a TLR2 agonist. Our results show that DC-SIGN dependent uptake of Mfa1+P. gingivalis strains by MoDCs resulted in lower intracellular killing and higher intracellular content of P. gingivalis. Moreover, Mfa1+P. gingivalis was mostly contained within single membrane vesicles, where it survived intracellularly. Survival was decreased by activation of TLR2 and/or autophagy. Mfa1+P. gingivalis strain did not induce significant levels of Rab5, LC3-II, and LAMP1. In contrast, P. gingivalis uptake through a DC-SIGN independent manner was associated with early endosomal routing through Rab5, increased LC3-II and LAMP-1, as well as the formation of double membrane intracellular phagophores, a characteristic feature of autophagy. These results suggest that selective engagement of DC-SIGN by Mfa-1+P. gingivalis promotes evasion of antibacterial autophagy and lysosome fusion, resulting in intracellular persistence in myeloid DCs; however TLR2 activation can overcome autophagy evasion and pathogen persistence in DCs.

  11. Isolation and Genetic Characterization of Toxoplasma gondii from Black Bears (Ursus americanus), Bobcats (Lynx rufus), and Feral Cats (Felis catus) from Pennsylvania.

    Science.gov (United States)

    Dubey, Jitender P; Verma, Shiv K; Calero-Bernal, Rafael; Cassinelli, Ana B; Kwok, Oliver C H; Van Why, Kyle; Su, Chunlei; Humphreys, Jan G

    2015-01-01

    Toxoplasma gondii infects virtually all warm-blooded hosts worldwide. Recently, attention has been focused on the genetic diversity of the parasite to explain its pathogenicity in different hosts. It has been hypothesized that interaction between feral and domestic cycles of T. gondii may increase unusual genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans, domestic animals, and wildlife. In the present study, we tested black bear (Ursus americanus), bobcat (Lynx rufus), and feral cat (Felis catus) from the state of Pennsylvania for T. gondii infection. Antibodies to T. gondii were found in 32 (84.2%) of 38 bears, both bobcats, and 2 of 3 feral cats tested by the modified agglutination test (cut off titer 1:25). Hearts from seropositive animals were bioassayed in mice, and viable T. gondii was isolated from 3 of 32 bears, 2 of 2 bobcats, and 2 of 3 feral cats. DNA isolated from culture-derived tachyzoites of these isolates was characterized using multilocus PCR-RFLP markers. Three genotypes were revealed, including ToxoDB PCR-RFLP genotype #1 or #3 (Type II, 1 isolate), #5 (Type 12, 3 isolates), and #216 (3 isolates), adding to the evidence of genetic diversity of T. gondii in wildlife in Pennsylvania. Pathogenicity of 3 T. gondii isolates (all #216, 1 from bear, and 2 from feral cat) was determined in outbred Swiss Webster mice; all three were virulent causing 100% mortality. Results indicated that highly mouse pathogenic strains of T. gondii are circulating in wildlife, and these strains may pose risk to infect human through consuming of game meat. Published 2014. This article is a U.S. Government work and is in the public domain in the USA.

  12. Simultaneous detection of viruses and Toxoplasma gondii in cerebrospinal fluid specimens by multiplex polymerase chain reaction-based reverse hybridization assay.

    Science.gov (United States)

    Del Prete, Raffaele; Di Taranto, Anna Maria; Lipsi, Maria Rosaria; Natalicchio, Maria Iole; Antonetti, Raffaele; Miragliotta, Giuseppe

    2009-04-01

    The lack of rapidity and the low sensitivity and specificity of traditional laboratory methods limits their usefulness in the laboratory diagnosis of viral central nervous system (CNS) infections. This study describes the use of a commercially available multiplex polymerase chain reaction (mPCR)-based reverse hybridization assay (RHA) for the simultaneous detection of the genomes of 8 viruses and Toxoplasma gondii in cerebrospinal fluids (CSF) from 181 patients suspected of having viral meningitis. Twenty-two/181 (12.15%) CSF samples resulted positive by mPCR. Eighteen/22 were positive for 1 viral pathogen, whereas a dual infection was detected in 4/22 samples. Epstein-Barr virus (EBV) was the most commonly detected virus (6/22), followed by herpes simplex virus type-1 (HSV-1) (5/22) and -2 (HSV-2) (4/22). Cytomegalovirus (CMV), human herpesvirus-6 (HHV-6), and Epstein-Barr virus (EBV) were detected in 1 specimen each. Two CSF samples were co-infected by HSV-1/HSV-2, 1 sample by HHV-6/T. gondii, and 1 sample by EBV/EV, respectively. Our data support the usefulness of mPCR as a rapid molecular method for the simultaneous detection of major viral pathogens and T. gondii in aseptic meningitis also to allow the earlier application of specific antiviral therapy.

  13. Optimizing Nanoelectrode Arrays for Scalable Intracellular Electrophysiology.

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    Abbott, Jeffrey; Ye, Tianyang; Ham, Donhee; Park, Hongkun

    2018-03-20

    Electrode technology for electrophysiology has a long history of innovation, with some decisive steps including the development of the voltage-clamp measurement technique by Hodgkin and Huxley in the 1940s and the invention of the patch clamp electrode by Neher and Sakmann in the 1970s. The high-precision intracellular recording enabled by the patch clamp electrode has since been a gold standard in studying the fundamental cellular processes underlying the electrical activities of neurons and other excitable cells. One logical next step would then be to parallelize these intracellular electrodes, since simultaneous intracellular recording from a large number of cells will benefit the study of complex neuronal networks and will increase the throughput of electrophysiological screening from basic neurobiology laboratories to the pharmaceutical industry. Patch clamp electrodes, however, are not built for parallelization; as for now, only ∼10 patch measurements in parallel are possible. It has long been envisioned that nanoscale electrodes may help meet this challenge. First, nanoscale electrodes were shown to enable intracellular access. Second, because their size scale is within the normal reach of the standard top-down fabrication, the nanoelectrodes can be scaled into a large array for parallelization. Third, such a nanoelectrode array can be monolithically integrated with complementary metal-oxide semiconductor (CMOS) electronics to facilitate the large array operation and the recording of the signals from a massive number of cells. These are some of the central ideas that have motivated the research activity into nanoelectrode electrophysiology, and these past years have seen fruitful developments. This Account aims to synthesize these findings so as to provide a useful reference. Summing up from the recent studies, we will first elucidate the morphology and associated electrical properties of the interface between a nanoelectrode and a cellular membrane

  14. Exploring NAD+ metabolism in host-pathogen interactions.

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    Mesquita, Inês; Varela, Patrícia; Belinha, Ana; Gaifem, Joana; Laforge, Mireille; Vergnes, Baptiste; Estaquier, Jérôme; Silvestre, Ricardo

    2016-03-01

    Nicotinamide adenine dinucleotide (NAD(+)) is a vital molecule found in all living cells. NAD(+) intracellular levels are dictated by its synthesis, using the de novo and/or salvage pathway, and through its catabolic use as co-enzyme or co-substrate. The regulation of NAD(+) metabolism has proven to be an adequate drug target for several diseases, including cancer, neurodegenerative or inflammatory diseases. Increasing interest has been given to NAD(+) metabolism during innate and adaptive immune responses suggesting that its modulation could also be relevant during host-pathogen interactions. While the maintenance of NAD(+) homeostatic levels assures an adequate environment for host cell survival and proliferation, fluctuations in NAD(+) or biosynthetic precursors bioavailability have been described during host-pathogen interactions, which will interfere with pathogen persistence or clearance. Here, we review the double-edged sword of NAD(+) metabolism during host-pathogen interactions emphasizing its potential for treatment of infectious diseases.

  15. Pathogenic adaptations to host-derived antibacterial copper

    Science.gov (United States)

    Chaturvedi, Kaveri S.; Henderson, Jeffrey P.

    2014-01-01

    Recent findings suggest that both host and pathogen manipulate copper content in infected host niches during infections. In this review, we summarize recent developments that implicate copper resistance as an important determinant of bacterial fitness at the host-pathogen interface. An essential mammalian nutrient, copper cycles between copper (I) (Cu+) in its reduced form and copper (II) (Cu2+) in its oxidized form under physiologic conditions. Cu+ is significantly more bactericidal than Cu2+ due to its ability to freely penetrate bacterial membranes and inactivate intracellular iron-sulfur clusters. Copper ions can also catalyze reactive oxygen species (ROS) generation, which may further contribute to their toxicity. Transporters, chaperones, redox proteins, receptors and transcription factors and even siderophores affect copper accumulation and distribution in both pathogenic microbes and their human hosts. This review will briefly cover evidence for copper as a mammalian antibacterial effector, the possible reasons for this toxicity, and pathogenic resistance mechanisms directed against it. PMID:24551598

  16. Profiling of Intracellular Metabolites: An Approach to Understanding the Characteristic Physiology of Mycobacterium leprae.

    Science.gov (United States)

    Miyamoto, Yuji; Mukai, Tetsu; Matsuoka, Masanori; Kai, Masanori; Maeda, Yumi; Makino, Masahiko

    2016-08-01

    Mycobacterium leprae is the causative agent of leprosy and also known to possess unique features such as inability to proliferate in vitro. Among the cellular components of M. leprae, various glycolipids present on the cell envelope are well characterized and some of them are identified to be pathogenic factors responsible for intracellular survival in host cells, while other intracellular metabolites, assumed to be associated with basic physiological feature, remain largely unknown. In the present study, to elucidate the comprehensive profile of intracellular metabolites, we performed the capillary electrophoresis-mass spectrometry (CE-MS) analysis on M. leprae and compared to that of M. bovis BCG. Interestingly, comparison of these two profiles showed that, in M. leprae, amino acids and their derivatives are significantly accumulated, but most of intermediates related to central carbon metabolism markedly decreased, implying that M. leprae possess unique metabolic features. The present study is the first report demonstrating the unique profiles of M. leprae metabolites and these insights might contribute to understanding undefined metabolism of M. leprae as well as pathogenic characteristics related to the manifestation of the disease.

  17. Introduction of caveolae structural proteins into the protozoan Toxoplasma results in the formation of heterologous caveolae but not caveolar endocytosis.

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    Bao Lige

    Full Text Available Present on the plasma membrane of most metazoans, caveolae are specialized microdomains implicated in several endocytic and trafficking mechanisms. Caveolins and the more recently discovered cavins are the major protein components of caveolae. Previous studies reported that caveolar invaginations can be induced de novo on the surface of caveolae-negative mammalian cells upon heterologous expression of caveolin-1. However, it remains undocumented whether other components in the transfected cells participate in caveolae formation. To address this issue, we have exploited the protozoan Toxoplasma as a heterologous expression system to provide insights into the minimal requirements for caveogenesis and caveolar endocytosis. Upon expression of caveolin-1, Toxoplasma accumulates prototypical exocytic caveolae 'precursors' in the cytoplasm. Toxoplasma expressing caveolin-1 alone, or in conjunction with cavin-1, neither develops surface-located caveolae nor internalizes caveolar ligands. These data suggest that the formation of functional caveolae at the plasma membrane in Toxoplasma and, by inference in all non-mammalian cells, requires effectors other than caveolin-1 and cavin-1. Interestingly, Toxoplasma co-expressing caveolin-1 and cavin-1 displays an impressive spiraled network of membranes containing the two proteins, in the cytoplasm. This suggests a synergistic activity of caveolin-1 and cavin-1 in the morphogenesis and remodeling of membranes, as illustrated for Toxoplasma.

  18. Hepatoprotective activity of Thymus vulgaris extract against Toxoplasma gondii infection

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    Nagwa Mostafa El-Sayed

    2017-05-01

    Full Text Available Objective: To evaluate the hepatoprotective activity of Thymus vulgaris (T. vulgaris extract against Toxoplasma gondii (T. gondii infection in experimentally infected mice. Methods: Sixty mice were divided into six groups (Group I–Group VI. Group I was normal control (non-infected, non-treated; Group II was non-infected and treated with T. vulgaris extract (500 mg/kg; Group III was T. gondii infected-non-immunosuppressed control; Group IV consisted of infected immunosuppressed mice; Group V was infected and treated with T. vulgaris extract; Group VI consisted of infected immunosuppressed mice treated with T. vulgaris extract. Hepatoprotective effect of T. vulgaris extract was evaluated by histopathological examination of tissue sections stained with hematoxylin and eosin, determination of liver function parameters (alanine aminotransaminase, aspartate aminotransaminase and alkaline phosphates, total bilirubin, total protein concentrations and assessment of hepatocytes genotoxicity by comet assay.Antigenotoxic effect of T. vulgaris was assessed by several comet assay parameters that were provided by the image analysis software, including % tailed cells, % of DNA in the tail, tail length, and tail moment. Results: Treatment with T. vulgaris in both Groups V and VI improved T. gondii induced pathological lesions in the infected liver that regressed to near the normal picture especially in Group V. Also, it restored the altered values of liver function parameters near to the normal levels significantly (P < 0.05 compared with Groups III and IV respectively. Regarding comet assay parameters, all of them were significantly increased (P < 0.05 after T. gondii infection (Group III and reached the greatest values in infected immunosuppressed group (Group IV compared to the normal controls (Group I. With treatment by T. vulgaris in Groups V and VI, there was a significant decrease (P < 0.05 in all values compared to Groups III and V respectively. The

  19. Frequency of Toxoplasma gondii antibodies in tufted capuchin monkeys (Cebus apella nigritus from an ecological station in the State of São Paulo, Brazil

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    Rodrigo Costa da Silva

    2013-02-01

    Full Text Available Toxoplasmosis is a worldwide zoonosis caused by Toxoplasma gondii, an obligate intracellular parasite protozoan. A large percentage of animals presents specific antibodies caused by a previous exposition, resulting in a chronic infection. Felides are the definitive hosts and the other warm-blooded animals, including primates, are the intermediate hosts. This study was aimed to determine the prevalence of T. gondii infection in free-living tufted capuchin monkeys (Cebus apella nigritus from an ecological station located on Mata de Santa Teresa, Ribeirão Preto, SP, Brazil. T. gondii antibodies were analyzed by modified agglutination test (MAT in serum samples of 36 tufted capuchin monkeys, considering eight as cut-off titer. From the studied animals, 3/36 (8.33%; CI95% 3.0-21.9% presented T. gondii antibodies, all with titer 32. No significative difference was observed relating to the sex (1/3 male and 2/3 female, and to the age (1/3 young and 2/3 adult (P>0.05. Thus, these results demonstrate the presence of T. gondii antibodies in primates from São Paulo state.

  20. Salmonella Intracellular Lifestyles and Their Impact on Host-to-Host Transmission.

    Science.gov (United States)

    Pucciarelli, M Graciela; García-Del Portillo, Francisco

    2017-07-01

    More than a century ago, infections by Salmonella were already associated with foodborne enteric diseases with high morbidity in humans and cattle. Intestinal inflammation and diarrhea are hallmarks of infections caused by nontyphoidal Salmonella serovars, and these pathologies facilitate pathogen transmission to the environment. In those early times, physicians and microbiologists also realized that typhoid and paratyphoid fever caused by some Salmonella serovars could be transmitted by "carriers," individuals outwardly healthy or at most suffering from some minor chronic complaint. In his pioneering study of the nontyphoidal serovar Typhimurium in 1967, Takeuchi published the first images of intracellular bacteria enclosed by membrane-bound vacuoles in the initial stages of the intestinal epithelium penetration. These compartments, called Salmonella -containing vacuoles, are highly dynamic phagosomes with differing biogenesis depending on the host cell type. Single-cell studies involving real-time imaging and gene expression profiling, together with new approaches based on genetic reporters sensitive to growth rate, have uncovered unprecedented heterogeneous responses in intracellular bacteria. Subpopulations of intracellular bacteria displaying fast, reduced, or no growth, as well as cytosolic and intravacuolar bacteria, have been reported in both in vitro and in vivo infection models. Recent investigations, most of them focused on the serovar Typhimurium, point to the selection of persisting bacteria inside macrophages or following an autophagy attack in fibroblasts. Here, we discuss these heterogeneous intracellular lifestyles and speculate on how these disparate behaviors may impact host-to-host transmissibility of Salmonella serovars.

  1. MicroRNA-155 promotes autophagy to eliminate intracellular mycobacteria by targeting Rheb.

    Science.gov (United States)

    Wang, Jinli; Yang, Kun; Zhou, Lin; Minhaowu; Wu, Yongjian; Zhu, Min; Lai, Xiaomin; Chen, Tao; Feng, Lianqiang; Li, Meiyu; Huang, Chunyu; Zhong, Qiu; Huang, Xi

    2013-01-01

    Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects one-third of the global population. It can live within macrophages owning to its ability to arrest phagolysosome biogenesis. Autophagy has recently been identified as an effective way to control the intracellular mycobacteria by enhancing phagosome maturation. In the present study, we demonstrate a novel role of miR-155 in regulating the autophagy-mediated anti-mycobacterial response. Both in vivo and in vitro studies showed that miR-155 expression was significantly enhanced after mycobacterial infection. Forced expression of miR-155 accelerated the autophagic response in macrophages, thus promoting the maturation of mycobacterial phagosomes and decreasing the survival rate of intracellular mycobacteria, while transfection with miR-155 inhibitor increased mycobacterial survival. However, macrophage-mediated mycobacterial phagocytosis was not affected after miR-155 overexpression or inhibition. Furthermore, blocking autophagy with specific inhibitor 3-methyladenine or silencing of autophagy related gene 7 (Atg7) reduced the ability of miR-155 to promote autophagy and mycobacterial elimination. More importantly, our study demonstrated that miR-155 bound to the 3'-untranslated region of Ras homologue enriched in brain (Rheb), a negative regulator of autophagy, accelerated the process of autophagy and sequential killing of intracellular mycobacteria by suppressing Rheb expression. Our results reveal a novel role of miR-155 in regulating autophagy-mediated mycobacterial elimination by targeting Rheb, and provide potential targets for clinical treatment.

  2. MicroRNA-155 promotes autophagy to eliminate intracellular mycobacteria by targeting Rheb.

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    Jinli Wang

    Full Text Available Mycobacterium tuberculosis is a hard-to-eradicate intracellular pathogen that infects one-third of the global population. It can live within macrophages owning to its ability to arrest phagolysosome biogenesis. Autophagy has recently been identified as an effective way to control the intracellular mycobacteria by enhancing phagosome maturation. In the present study, we demonstrate a novel role of miR-155 in regulating the autophagy-mediated anti-mycobacterial response. Both in vivo and in vitro studies showed that miR-155 expression was significantly enhanced after mycobacterial infection. Forced expression of miR-155 accelerated the autophagic response in macrophages, thus promoting the maturation of mycobacterial phagosomes and decreasing the survival rate of intracellular mycobacteria, while transfection with miR-155 inhibitor increased mycobacterial survival. However, macrophage-mediated mycobacterial phagocytosis was not affected after miR-155 overexpression or inhibition. Furthermore, blocking autophagy with specific inhibitor 3-methyladenine or silencing of autophagy related gene 7 (Atg7 reduced the ability of miR-155 to promote autophagy and mycobacterial elimination. More importantly, our study demonstrated that miR-155 bound to the 3'-untranslated region of Ras homologue enriched in brain (Rheb, a negative regulator of autophagy, accelerated the process of autophagy and sequential killing of intracellular mycobacteria by suppressing Rheb expression. Our results reveal a novel role of miR-155 in regulating autophagy-mediated mycobacterial elimination by targeting Rheb, and provide potential targets for clinical treatment.

  3. A new type of intracellular retention signal identified in a pestivirus structural glycoprotein.

    Science.gov (United States)

    Burrack, Sandra; Aberle, Daniel; Bürck, Jochen; Ulrich, Anne S; Meyers, Gregor

    2012-08-01

    Sorting of membrane proteins into intracellular organelles is crucial for cell function. Viruses exploit intracellular transport and retention systems to concentrate envelope proteins at the site of virus budding. In pestiviruses, a group of important pathogens of pigs and ruminants closely related to human hepatitis C virus, the E(rns) protein translated from the viral RNA is secreted from the infected cells and found in the serum of infected animals. Secretion of the protein is regarded as crucial for its function as a viral virulence factor associated with its RNase activity. However, ∼95% of the E(rns) molecules are retained within the infected cell. Fusion of different E(rns) fragments to the C terminus of CD72 allowed identification of a retention signal within the C-terminal 65 aa of the viral protein. This C-terminal sequence represents its membrane anchor and folds into an amphipathic helix binding in-plane to the membrane surface. Residues L183, I190, and L208 are important for intracellular location of E(rns). Presentation of the retention signal on the cytoplasmic instead of the luminal face of the ER membrane in CD8α fusion proteins still led to retention. Thus, E(rns) contains in its C-terminal amphipathic helix an intracellular retention signal that is active on both faces of the membrane.

  4. AMPK in Pathogens.

    Science.gov (United States)

    Mesquita, Inês; Moreira, Diana; Sampaio-Marques, Belém; Laforge, Mireille; Cordeiro-da-Silva, Anabela; Ludovico, Paula; Estaquier, Jérôme; Silvestre, Ricardo

    2016-01-01

    During host-pathogen interactions, a complex web of events is crucial for the outcome of infection. Pathogen recognition triggers powerful cellular signaling events that is translated into the induction and maintenance of innate and adaptive host immunity against infection. In opposition, pathogens employ active mechanisms to manipulate host cell regulatory pathways toward their proliferation and survival. Among these, subversion of host cell energy metabolism by pathogens is currently recognized to play an important role in microbial growth and persistence. Extensive studies have documented the role of AMP-activated protein kinase (AMPK) signaling, a central cellular hub involved in the regulation of energy homeostasis, in host-pathogen interactions. Here, we highlight the most recent advances detailing how pathogens hijack cellular metabolism by suppressing or increasing the activity of the host energy sensor AMPK. We also address the role of lower eukaryote AMPK orthologues in the adaptive process to the host microenvironment and their contribution for pathogen survival, differentiation, and growth. Finally, we review the effects of pharmacological or genetic AMPK modulation on pathogen growth and persistence.

  5. Potatoes, pathogens and pests

    NARCIS (Netherlands)

    Lazebnik, Jenny

    2017-01-01

    Currently, fungicides are necessary to protect potato crops against late blight, Phytophthora infestans, one of the world’s most damaging crop pathogens. The introgression of plant resistance genes from wild potato species targeted specifically to the late blight pathogen into

  6. Food-borne pathogens

    International Nuclear Information System (INIS)

    Niemand, J.G.

    1985-01-01

    The Salmonella scare reinforced the importance of never taking chances when it comes to controlling pathogens. The issue has been resolved by radurisation. The article deals with the various pathogens that can effect food and argues the case for radurisation in dealing with them. It also looks at some of the other food products that can be treated using this process

  7. Effect of 3-bromopyruvate and atovaquone on infection during in vitro interaction of Toxoplasma gondii and LLC-MK2 cells.

    Science.gov (United States)

    de Lima, Loyze Paola O; Seabra, Sergio H; Carneiro, Henrique; Barbosa, Helene S

    2015-09-01

    Toxoplasma gondii infection can be severe during pregnancy and in immunocompromised patients. Current therapies for toxoplasmosis are restricted to tachyzoites and have little or no effect on bradyzoites, which are maintained in tissue cysts. Consequently, new therapeutic alternatives have been proposed as the use of atovaquone has demonstrated partial efficacy against tachyzoites and bradyzoites. This work studies the effect of 3-bromopyruvate (3-BrPA), a compound that is being tested against cancer cells, on the infection of LLC-MK2 cells with T. gondii tachyzoites, RH strain. No effect of 3-BrPA on host cell proliferation or viability was observed, but it inhibited the proliferation of T. gondii. The incubation of cultures with lectin Dolichos biflorus agglutinin (DBA) showed the development of cystogenesis, and an ultrastructural analysis of parasite intracellular development confirmed morphological characteristics commonly found in tissue cysts. Moreover, the presence of degraded parasites and the influence of 3-BrPA on endodyogeny were observed. Infected cultures were alternatively treated with a combination of this compound plus atovaquone. This resulted in a 73% reduction in intracellular parasites after 24 h of treatment and a 71% reduction after 48 h; cyst wall formation did not occur in these cultures. Therefore, we conclude that the use of 3-BrPA may serve as an important tool for the study of (i) in vitro cystogenesis; (ii) parasite metabolism, requiring a deeper understanding of the target of action of this compound on T. gondii; (iii) the alternative parasite metabolic pathways; and (iv) the molecular/cellular mechanisms that trigger parasite death. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  8. Bothrops pirajai snake venom L-amino acid oxidase: in vitro effects on infection of Toxoplasma gondii in human foreskin fibroblasts

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    Luiz F. M. Izidoro

    2011-06-01

    Full Text Available The effect of an L-amino acid oxidase isolated from Bothrops pirajai snake venom (BpirLAAO-I was investigated on infection of Toxoplasma gondii in human foreskin fibroblasts (HFF. The cytotoxic activity of BpirLAAO-I on HFF cells showed a dose-dependent toxicity with median cytotoxic dose (TD50 of 11.8 µg/mL. BpirLAAO-I induced considerable dose-dependent decrease in the T. gondii infection index under two different conditions, treatment of tachyzoites before infection or treatment of HFF cells after infection. A maximal inhibition of infection (56% was found for treatment before infection, with a median inhibitory dose (ID50 at 1.83 µg/mL and selectivity index (SI at 6.45. For treatment after infection, it was observed a maximal inhibition of infection at 65%, ID50 of 1.20 µg/mL and SI of 9.83. The treatment before infection was also effective to reduce intracellular parasitism up to 62%, although presenting higher values of ID50 (3.14 µg/mL and lower values of SI (3.76. However, treatment after infection was not effective, suggesting that the enzyme seems to have no effect on the parasite intracellular replication for this condition. In conclusion, BpirLAAO-I was more effective to inhibit the infection of neighboring cells and consequently parasite dissemination than primary infection and parasite replication. Thus, the effect of BpirLAAO-I described herein could be taken into account for the development of new synthetic anti-parasite therapeutic agents.

  9. Immunization with a DNA vaccine encoding Toxoplasma gondii Superoxide dismutase (TgSOD) induces partial immune protection against acute toxoplasmosis in BALB/c mice.

    Science.gov (United States)

    Liu, Yuan; Cao, Aiping; Li, Yawen; Li, Xun; Cong, Hua; He, Shenyi; Zhou, Huaiyu

    2017-06-07

    Toxoplasma gondii (T. gondii) is an obligate intracellular protozoan parasite that infects all warm-blooded animals including humans and causes toxoplasmosis. An effective vaccine could be an ideal choice for preventing and controlling toxoplasmosis. T. gondii Superoxide dismutase (TgSOD) might participate in affecting the intracellular growth of both bradyzoite and tachyzoite forms. In the present study, the TgSOD gene was used to construct a DNA vaccine (pEGFP-SOD). TgSOD gene was amplified and inserted into eukaryotic vector pEGFP-C1 and formed the DNA vaccine pEGFP-SOD. Then the BALB/c mice were immunized intramuscularly with the DNA vaccine and those injected with pEGFP-C1, PBS or nothing were treated as controls. Four weeks after the last immunization, all mouse groups followed by challenging intraperitoneally with tachyzoites of T. gondii ME49 strain. Results showed higher levels of total IgG, IgG2α in the sera and interferon gamma (IFN-γ) in the splenocytes from pEGFP-SOD inoculated mice than those unvaccinated, or inoculated with either empty plasmid vector or PBS. The proportions of CD4 + T cells and CD8 + T cells in the spleen from pEGFP-SOD inoculated mice were significantly (p < 0.05) increased compared to control groups. In addition, the survival time of mice immunized with pEGFP-SOD was significantly prolonged as compared to the controls (p < 0.05) although all the mice died. The present study revealed that the DNA vaccine triggered strong humoral and cellular immune responses, and aroused partial protective immunity against acute T. gondii infection in BALB/c mice. The collective data suggests the SOD may be a potential vaccine candidate for further development.

  10. Pathogen inactivation techniques.

    Science.gov (United States)

    Pelletier, J P R; Transue, S; Snyder, E L

    2006-01-01

    The desire to rid the blood supply of pathogens of all types has led to the development of many technologies aimed at the same goal--eradication of the pathogen(s) without harming the blood cells or generating toxic chemical agents. This is a very ambitious goal, and one that has yet to be achieved. One approach is to shun the 'one size fits all' concept and to target pathogen-reduction agents at the Individual component types. This permits the development of technologies that might be compatible with, for example, plasma products but that would be cytocidal and thus incompatible with platelet concentrates or red blood cell units. The technologies to be discussed include solvent detergent and methylene blue treatments--designed to inactivate plasma components and derivatives; psoralens (S-59--amotosalen) designed to pathogen-reduce units of platelets; and two products aimed at red blood cells, S-303 (a Frale--frangible anchor-linker effector compound) and Inactine (a binary ethyleneimine). A final pathogen-reduction material that might actually allow one material to inactivate all three blood components--riboflavin (vitamin B2)--is also under development. The sites of action of the amotosalen (S-59), the S-303 Frale, Inactine, and riboflavin are all localized in the nucleic acid part of the pathogen. Solvent detergent materials act by dissolving the plasma envelope, thus compromising the integrity of the pathogen membrane and rendering it non-infectious. By disrupting the pathogen's ability to replicate or survive, its infectivity is removed. The degree to which bacteria and viruses are affected by a particular pathogen-reducing technology relates to its Gram-positive or Gram-negative status, to the sporulation characteristics for bacteria, and the presence of lipid or protein envelopes for viruses. Concerns related to photoproducts and other breakdown products of these technologies remain, and the toxicology of pathogen-reduction treatments is a major ongoing area

  11. Using molecular epidemiology to track Toxoplasma gondii from terrestrial carnivores to marine hosts: implications for public health and conservation.

    Science.gov (United States)

    VanWormer, Elizabeth; Miller, Melissa A; Conrad, Patricia A; Grigg, Michael E; Rejmanek, Daniel; Carpenter, Tim E; Mazet, Jonna A K

    2014-01-01

    Environmental transmission of the zoonotic parasite Toxoplasma gondii, which is shed only by felids, poses risks to human and animal health in temperate and tropical ecosystems. Atypical T. gondii genotypes have been linked to severe disease in people and the threatened population of California sea otters. To investigate land-to-sea parasite transmission, we screened 373 carnivores (feral domestic cats, mountain lions, bobcats, foxes, and coyotes) for T. gondii infection and examined the distribution of genotypes in 85 infected animals sampled near the sea otter range. Nested PCR-RFLP analyses and direct DNA sequencing at six independent polymorphic genetic loci (B1, SAG1, SAG3, GRA6, L358, and Apico) were used to characterize T. gondii strains in infected animals. Strains consistent with Type X, a novel genotype previously identified in over 70% of infected sea otters and four terrestrial wild carnivores along the California coast, were detected in all sampled species, including domestic cats. However, odds of Type X infection were 14 times higher (95% CI: 1.3-148.6) for wild felids than feral domestic cats. Type X infection was also linked to undeveloped lands (OR = 22, 95% CI: 2.3-250.7). A spatial cluster of terrestrial Type II infection (P = 0.04) was identified in developed lands bordering an area of increased risk for sea otter Type II infection. Two spatial clusters of animals infected with strains consistent with Type X (P ≤ 0.01) were detected in less developed landscapes. Differences in T. gondii genotype prevalence among domestic and wild felids, as well as the spatial distribution of genotypes, suggest co-existing domestic and wild T. gondii transmission cycles that likely overlap at the interface of developed and undeveloped lands. Anthropogenic development driving contact between these cycles may increase atypical T. gondii genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans, domestic animals

  12. Using molecular epidemiology to track Toxoplasma gondii from terrestrial carnivores to marine hosts: implications for public health and conservation.

    Directory of Open Access Journals (Sweden)

    Elizabeth VanWormer

    Full Text Available Environmental transmission of the zoonotic parasite Toxoplasma gondii, which is shed only by felids, poses risks to human and animal health in temperate and tropical ecosystems. Atypical T. gondii genotypes have been linked to severe disease in people and the threatened population of California sea otters. To investigate land-to-sea parasite transmission, we screened 373 carnivores (feral domestic cats, mountain lions, bobcats, foxes, and coyotes for T. gondii infection and examined the distribution of genotypes in 85 infected animals sampled near the sea otter range.Nested PCR-RFLP analyses and direct DNA sequencing at six independent polymorphic genetic loci (B1, SAG1, SAG3, GRA6, L358, and Apico were used to characterize T. gondii strains in infected animals. Strains consistent with Type X, a novel genotype previously identified in over 70% of infected sea otters and four terrestrial wild carnivores along the California coast, were detected in all sampled species, including domestic cats. However, odds of Type X infection were 14 times higher (95% CI: 1.3-148.6 for wild felids than feral domestic cats. Type X infection was also linked to undeveloped lands (OR = 22, 95% CI: 2.3-250.7. A spatial cluster of terrestrial Type II infection (P = 0.04 was identified in developed lands bordering an area of increased risk for sea otter Type II infection. Two spatial clusters of animals infected with strains consistent with Type X (P ≤ 0.01 were detected in less developed landscapes.Differences in T. gondii genotype prevalence among domestic and wild felids, as well as the spatial distribution of genotypes, suggest co-existing domestic and wild T. gondii transmission cycles that likely overlap at the interface of developed and undeveloped lands. Anthropogenic development driving contact between these cycles may increase atypical T. gondii genotypes in domestic cats and facilitate transmission of potentially more pathogenic genotypes to humans

  13. Seroprevalence of Bartonella species, Coxiella burnetii and Toxoplasma gondii among patients with hematological malignancies: A pilot study in Romania.

    Science.gov (United States)

    Messinger, C J; Gurzau, E S; Breitschwerdt, E B; Tomuleasa, C I; Trufan, S J; Flonta, M M; Maggi, R G; Berindan-Neagoe, I; Rabinowitz, P M

    2017-09-01

    Patients receiving immunosuppressive cancer treatments in settings where there is a high degree of human-animal interaction may be at increased risk for opportunistic zoonotic infections or reactivation of latent infections. We sought to determine the seroprevalence of selected zoonotic pathogens among patients diagnosed with haematologic malignancies and undergoing chemotherapeutic treatments in Romania, where much of the general population lives and/or works in contact with livestock. A convenience sample of 51 patients with haematologic cancer undergoing chemotherapy at a referral clinic in Cluj-Napoca, Romania, was surveyed regarding animal exposures. Blood samples were obtained and tested for evidence of infection with Bartonella species, Coxiella burnetii and Toxoplasma gondii, which are important opportunistic zoonotic agents in immunocompromised individuals. 58.8% of participants reported living or working on a farm, and living or working on a farm was associated with contact with livestock and other animals. 37.5% of participants were IgG seroreactive against one or more of five Bartonella antigens, and seroreactivity was statistically associated with living on farms. Farm dwellers were 3.6 times more likely to test IgG seroreactive to Bartonella antibodies than non-farm dwellers. 47.1% of the participants tested T. gondii IgG positive and 13.7% tested C. burnetii IgG positive, indicating past or latent infection. C. burnetii IgM antibodies were detected in four participants (7.8%), indicating possible recent infection. These results indicate that a large proportion of patients with haematologic cancer in Romania may be at risk for zoonotic infections or for reactivation of latent zoonotic infections, particularly with respect to Bartonella species. Special attention should be paid to cancer patients' exposure to livestock and companion animals in areas where much of the population lives in rural settings. © 2017 Blackwell Verlag GmbH.

  14. Detection of Toxoplasma gondii oocysts in soils in northwestern China using a new semi-nested PCR assay.

    Science.gov (United States)

    Wang, Meng; Meng, Peng; Ye, Qiang; Pu, Yuan-Hua; Yang, Xiao-Yu; Luo, Jian-Xun; Zhang, Nian-Zhang; Zhang, De-Lin

    2014-09-28

    Toxoplasma gondii is a zoonotic pathogen that can infect a range of animals and humans. Ingestion of T. gondii oocysts in soil is a significant transmission route for humans and animals acquiring toxoplasmosis. In the present study, we developed a new semi-nested PCR method to determine T. gondii oocysts distribution in soils in northwestern China. The one tube semi-nested PCR assay was developed to detect the oocysts of T. gondii in soil, targeting the repetitive 529 bp fragment of T. gondii genomic DNA. Then a total of 268 soil samples, including 148 samples from Gansu Province and 120 samples from Qinghai Province, northwestern China, were examined by the semi-nested PCR method. One third of the positive samples were sequenced. The sensitivity of the semi-nested PCR assay was 10(2)  T. gondii oocysts in 5 g soil sample. Investigation of soil samples from northwestern China showed that 34 out of 268 soil samples (12.69%) were T. gondii positive. Sequences of the partial 529 bp fragments varied from 0-1.2% among the sequenced samples. The prevalence of T. gondii oocysts in soil from cities (24/163) was slightly higher than that in soils from pasturing areas (10/105) (P = 0.21). Among the different regions in cities, the prevalence of T. gondii oocysts in soils from parks was 14.15%, whereas that in soils from schools was 19.05%. The present study firstly reported the prevalence of T. gondii oocysts in soils in northwest China using a novel semi-nested PCR assay, which provided baseline data for the effective prevention and control of toxoplasmosis in this region.

  15. Exposure to selected Pathogens in to selected pathogens in Geoffroy's cats and domestic carnivores from central Argentina.

    Science.gov (United States)

    Uhart, Marcela M; Rago, M Virginia; Marull, Carolina A; Ferreyra, Hebe del Valle; Pereira, Javier A

    2012-10-01

    Wild carnivores share a high percentage of parasites and viruses with closely related domestic carnivores. Because of increased overlap and potential contact with domestic species, we conducted a retrospective serosurvey for 11 common carnivore pathogens in 40 Geoffroy's cats (Leopardus geoffroyi) sampled between 2000 and 2008 within or near two protected areas in central Argentina (Lihué Calel National Park, La Pampa, and Campos del Tuyú National Park, Buenos Aires), as well as five domestic cats and 11 domestic dogs from catde ranches adjacent to Lihué Calel Park. Geoffroy's cats had detectable antibody to canine distemper virus (CDV), feline calicivirus (FCV), feline coronavirus, feline panleukopenia virus (FPV), Toxoplasma gondii, Leptospira interrogans (serovars Ictero/Icter and Ballum), and Dirofilaria immitis. None of the wild cats had antibodies to feline herpesvirus, feline immunodeficiency virus (FIV), feline leukemia virus, or rabies virus. Domestic dogs had antibodies to CDV, canine adenovirus, canine herpesvirus, and canine parvovirus. Antibodies to FPV, FCV, FIV, and T. gondii were found in domestic cats. We provide the first data on exposure of free-ranging Geoffroy's cats to pathogens at two sites within the core area of the species distribution range, including the first report of antibodies to CDV in this species. We encourage continued monitoring for diseases in wild and domestic carnivores as well as preventive health care for domestic animals, particularly in park buffer zones where overlap is greatest.

  16. Processes for managing pathogens.

    Science.gov (United States)

    Godfree, Alan; Farrell, Joseph

    2005-01-01

    Wastewater contains human, animal, and plant pathogens capable of causing viral, bacterial, or parasitic infections. There are several routes whereby sewage pathogens may affect human health, including direct contact, contamination of food crops, zoonoses, and vectors. The range and numbers of pathogens in municipal wastewater vary with the level of endemic disease in the community, discharges from commercial activities, and seasonal factors. Regulations to control pathogen risk in the United States and Europe arising from land application of biosolids are based on the concept of multiple barriers to the prevention of transmission. The barriers are (i) treatment to reduce pathogen content and vector attraction, (ii) restrictions on crops grown on land to which biosolids have been applied, and (iii) minimum intervals following application and grazing or harvesting. Wastewater treatment reduces number of pathogens in the wastewater by concentrating them with the solids in the sludge. Although some treatment processes are designed specifically to inactivate pathogens, many are not, and the actual mechanisms of microbial inactivation are not fully understood for all processes. Vector attraction is reduced by stabilization (reduction of readily biodegradable material) and/or incorporation immediately following application. Concerns about health risks have renewed interest in the effects of treatment (on pathogens) and advanced treatment methods, and work performed in the United States suggests that Class A pathogen reduction can be achieved less expensively than previously thought. Effective pathogen risk management requires control to the complete chain of sludge treatment, biosolids handling and application, and post-application activities. This may be achieved by adherence to quality management systems based on hazard analysis critical control point (HACCP) principles.

  17. Intracellular, genetic or congenital immunisation--transgenic approaches to increase disease resistance of farm animals.

    Science.gov (United States)

    Müller, M; Brem, G

    1996-01-26

    Novel approaches to modify disease resistance or susceptibility in livestock are justified not only by economical reasons and with respect to animal welfare but also by recent advancements in molecular genetics. The control or elimination of infectious pathogens in farm animals is historically achieved by the use of vaccines and drugs and by quarantine safeguards and eradication. Currently, research on the improvement of disease resistance based on nucleic acid technology focuses on two main issues: additive gene transfer and the development of nucleic acid vaccines. The strategies aim at the stable or transient expression of components known to influence non-specific or specific host defence mechanisms against infectious pathogens. Thus, candidates for gene transfer experiments include all genes inducing or conferring innate and acquired immunity as well as specific disease resistance genes. Referring to the site and mode of action and the source of the effective agent the strategies are termed 'intracellular', 'genetic' and 'congenital' immunisation. The targeted disruption (deletive gene transfer) of disease susceptibility genes awaits the establishment of totipotential embryonic cell lineages in farm animals. The cytokine network regulates cellular viability, growth and differentiation in physiological and pathophysiological states. The identification of the JAK-STAT pathway used by many cytokines for their intracellular signal propagation has provided not only new target molecules for modulating the immune response but will also permit the further elucidation of host-pathogen interactions and resistance mechanisms.

  18. Dynamics of gradient formation by intracellular shuttling

    Energy Technology Data Exchange (ETDEWEB)

    Berezhkovskii, Alexander M. [Mathematical and Statistical Computing Laboratory, Division of Computational Bioscience, Center for Information Technology, National Institutes of Health, Bethesda, Maryland 20892 (United States); Shvartsman, Stanislav Y. [Department of Chemical and Biological Engineering and Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, New Jersey 08544 (United States)

    2015-08-21

    A number of important cellular functions rely on the formation of intracellular protein concentration gradients. Experimental studies discovered a number of mechanisms for the formation of such gradients. One of the mechanisms relies on the intracellular shuttling of a protein that interconverts between the two states with different diffusivities, under the action of two enzymes, one of which is localized to the plasma membrane, whereas the second is uniformly distributed in the cytoplasm. Recent work reported an analytical solution for the steady state gradient in this mechanism, obtained in the framework of a one-dimensional reaction-diffusion model. Here, we study the dynamics in this model and derive analytical expressions for the Laplace transforms of the time-dependent concentration profiles in terms of elementary transcendental functions. Inverting these transforms numerically, one can obtain time-dependent concentration profiles of the two forms of the protein.

  19. Leishmania hijacking of the macrophage intracellular compartments.

    Science.gov (United States)

    Liévin-Le Moal, Vanessa; Loiseau, Philippe M

    2016-02-01

    Leishmania spp., transmitted to humans by the bite of the sandfly vector, are responsible for the three major forms of leishmaniasis, cutaneous, diffuse mucocutaneous and visceral. Leishmania spp. interact with membrane receptors of neutrophils and macrophages. In macrophages, the parasite is internalized within a parasitophorous vacuole and engages in a particular intracellular lifestyle in which the flagellated, motile Leishmania promastigote metacyclic form differentiates into non-motile, metacyclic amastigote form. This phenomenon is induced by Leishmania-triggered events leading to the fusion of the parasitophorous vacuole with vesicular members of the host cell endocytic pathway including recycling endosomes, late endosomes and the endoplasmic reticulum. Maturation of the parasitophorous vacuole leads to the intracellular proliferation of the Leishmania amastigote forms by acquisition of host cell nutrients while escaping host defense responses. © 2015 FEBS.

  20. Reduction of intracellular glutathione content and radiosensitivity

    International Nuclear Information System (INIS)

    Vos, O.; Schans, G.P. van der; Roos-Verheij, W.S.D.

    1986-05-01

    The intracellular glutathione (GSH) content in HeLa, CHO and V79 cells was reduced by incubating the cells in growth medium containing buthionine sulfoximine (BSO) or diethyl maleate (DEM). Clonogenicity, single strand DNA breaks (ssb) and double strand DNA breaks (dsb) were used as criteria for radiation induced damage after X- or γ irradiation. In survival experiments DEM gave a slightly larger sensitization although it gave a smaller reduction of the intracellular GSH. In general, sensitization was larger for dsb than for ssb, also the reduction of the OER was generally larger for dsb than for ssb. This may be due to the higher dose rate in case of dsb experiments resulting in a higher rate of radiochemical oxygen consumption. In general, no effect was found on post-irradiation repair of ssb and dsb. (Auth.)

  1. Reduction of intracellular glutathione content and radiosensitivity

    International Nuclear Information System (INIS)

    Vos, O.; Schans, G.P. van der; Roos-Verheij, W.S.D.

    1986-01-01

    The intracellular glutathione (GSH) content of HeLa, CHO and V79 cells was reduced by incubating the cells in growth medium containing buthionine sulphoximine or diethyl maleate (DEM). Clonogenicity, single-strand DNA breaks (ssb) and double-strand DNA breaks (dsb) were used as criteria for radiation-induced damage after X- or γ-irradiation. In survival experiments, DEM gave a slightly larger sensitization although it gave a smaller reduction of the intracellular GSH. In general, sensitization was larger for dsb than for ssb, also the reduction of the o.e.r. was generally larger for dsb than for ssb. This may be due to the higher dose rate in case of dsb experiments resulting in a higher rate of radiochemical oxygen consumption. In general, no effect was found on post-irradiation repair of ssb and dsb. (author)

  2. Intracellular mechanisms of solar water disinfection

    Science.gov (United States)

    Castro-Alférez, María; Polo-López, María Inmaculada; Fernández-Ibáñez, Pilar

    2016-12-01

    Solar water disinfection (SODIS) is a zero-cost intervention measure to disinfect drinking water in areas of poor access to improved water sources, used by more than 6 million people in the world. The bactericidal action of solar radiation in water has been widely proven, nevertheless the causes for this remain still unclear. Scientific literature points out that generation of reactive oxygen species (ROS) inside microorganisms promoted by solar light absorption is the main reason. For the first time, this work reports on the experimental measurement of accumulated intracellular ROS in E. coli during solar irradiation. For this experimental achievement, a modified protocol based on the fluorescent probe dichlorodihydrofluorescein diacetate (DCFH-DA), widely used for oxidative stress in eukaryotic cells, has been tested and validated for E. coli. Our results demonstrate that ROS and their accumulated oxidative damages at intracellular level are key in solar water disinfection.

  3. Comparative genomics of transport proteins in probiotic and pathogenic Escherichia coli and Salmonella enterica strains.

    Science.gov (United States)

    Do, Jimmy; Zafar, Hassan; Saier, Milton H

    2017-06-01

    Escherichia coli is a genetically diverse species that can be pathogenic, probiotic, commensal, or a harmless laboratory strain. Pathogenic strains of E. coli cause urinary tract infections, diarrhea, hemorrhagic colitis, and pyelonephritis, while the two known probiotic E. coli strains combat inflammatory bowel disease and play a role in immunomodulation. Salmonella enterica, a close relative of E. coli, includes two important pathogenic serovars, Typhi and Typhimurium, causing typhoid fever and enterocolitis in humans, respectively, with the latter strain also causing a lethal typhoid fever-like disease in mice. In this study, we identify the transport systems and their substrates within seven E. coli strains: two probiotic strains, two extracellular pathogens, two intracellular pathogens, and K-12, as well as the two intracellular pathogenic S. enterica strains noted above. Transport systems characteristic of each probiotic or pathogenic species were thus identified, and the tabulated results obtained with all of these strains were compared. We found that the probiotic and pathogenic strains generally contain more iron-siderophore and sugar transporters than E. coli K-12. Pathogens have increased numbers of pore-forming toxins, protein secretion systems, decarboxylation-driven Na + exporters, electron flow-driven monovalent cation exporters, and putative transporters of unknown function compared to the probiotic strains. Both pathogens and probiotic strains encode metabolite transporters that reflect their intracellular versus extracellular environments. The results indicate that the probiotic strains live extracellularly. It seems that relatively few virulence factors can convert a beneficial or commensal microorganism into a pathogen. Taken together, the results reveal the distinguishing features of these strains and provide a starting point for future engineering of beneficial enteric bacteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Development of growth rate measuring method for intracellular, parasitic acid-fast bacteria using radioisotopes

    International Nuclear Information System (INIS)

    Nakata, Noboru; Fukutomi, Yasuo

    1998-01-01

    To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using 14 C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO 2 was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)

  5. Development of growth rate measuring method for intracellular, parasitic acid-fast bacteria using radioisotopes

    Energy Technology Data Exchange (ETDEWEB)

    Nakata, Noboru; Fukutomi, Yasuo [National Inst. of Infectious Deseases, Tokyo (Japan)

    1998-02-01

    To prevent and treat infections diseases caused by pathogenic acid-fast bacteria such as Mycobacterium leprae, Tubercle bacillus, it is important to elucidate the mechanisms of intracellular proliferations of these bacteria. This research project was started to make DNA library using a new constructed shuttle vector. Development of in vitro evaluation method for intracellular proliferation of mycobacterium and its transformed cells was attempted on the basis of Buddemeyer method. This method was able to precisely determine the metabolic activities as low as those in leprae and its modified method using {sup 14}C-palmitic acid was highly sensitive and the results were obtainable in a shorter period. The generated CO{sub 2} was satisfactorily absorbed into scintillator without using a filter paper. A new culture medium from which arginine, a NO-producing compound was eliminated was used to repress the sterilizing effects of NO, but the metabolic activities of leprae was not enhanced. (M.N.)

  6. Intracellular serpins, firewalls and tissue necrosis.

    Science.gov (United States)

    Marciniak, Stefan J; Lomas, David A

    2008-02-01

    Luke and colleagues have recently attributed a new role to a member of the serpin superfamily of serine proteinase inhibitors. They have used Caenorhabditis elegans to show that an intracellular serpin is crucial for maintaining lysosomal integrity. We examine the role of this firewall in preventing necrosis and attempt to integrate this with current theories of stress-induced protein degradation. We discuss how mutant serpins cause disease either through polymerization or now, perhaps, by unleashing necrosis.

  7. Producción de anticuerpos policlonales IgG contra una proteína con actividad de óxido nítrico sintetasa de Toxoplasma gondii recombinante (NOS-Tg-r y marcación inmunológica en taquizoítoso Production of Polyclonal Antibodies against Toxoplasma gondii Recombinant protein with Nitric Oxide Synthase activity and immunologic marking in Tachyzoites

    Directory of Open Access Journals (Sweden)

    Jonathan Mauricio Padilla-Londoño

    2008-06-01

    Full Text Available La enzima óxido nítrico sintetasa ha sido estudiada en mamíferos; en los últimos años se ha descrito que existe también en protozoos, pero se desconocen aspectos importantes de su función. Se logró producir anticuerpos policlonales contra la proteína recombinante con actividad de óxido nítrico sintetasa (NOS-Tg-r de Toxoplasma gondii y realizar marcación inmunológica en taquizoítos. Se usaron dos conejos Nueva Zelanda (Oryctolagus cuniculusque se inmunizaron por vía intramuscular con NOS-Tg-r, y dos tipos de adyuvantes, hidróxido de aluminio y adyuvante de Freund. Se comprobó la presencia de anticuerpos policlonales con la técnica de ensayo inmunoenzimático indirecto. Los resultados obtenidos mostraron que a NOS-Tg-r con adyuvante de Freund indujo mayor respuesta inmune que la de la NOS-Tg-r con hidróxido aluminio p 0,005. Para verificar si había reacción cruzada, se realizó una prueba ELISA utilizando como antígenos: metaloproteasa de T. gondii recombinante, cisteína proteasa 5 de Entamoeba histolytica recombinante, albúmina al 2%, hidróxido de aluminio y adyuvante de Freund. Los valores obtenidos con sueros preinmunes y contra proteínas alternas no superaron el punto de corte (0,069, lo cual indica que los anticuerpos policlonales obtenidos son específicos para NOS-Tg-r. Se realizó marcación inmunológica en taquizoítos de Toxoplasma gondii con inmunofluorescencia indirecta que mostró una marcación difusa a nivel de citoplasma y confirmó la presencia de esta proteína en los taquizoítos.The nitric oxide synthase (NOSis an enzyme well described on mammals but little is known about the role of these enzymes on pathogenic parasites. We produced polyclonal antibodies against a recombinant NOS enzyme from Toxoplasma gondii nd e lso er formed n mmunol locali zation of the enzyme on tachyzoites. We used two New Zealand rabbits (Oryctolagus cuniculus to perform intramuscular immunization and we used two types of

  8. Fluorescent nanoparticles for intracellular sensing: A review

    International Nuclear Information System (INIS)

    Ruedas-Rama, Maria J.; Walters, Jamie D.; Orte, Angel; Hall, Elizabeth A.H.

    2012-01-01

    Highlights: ► Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. ► Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. ► Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  9. Fluorescent nanoparticles for intracellular sensing: A review

    Energy Technology Data Exchange (ETDEWEB)

    Ruedas-Rama, Maria J., E-mail: mjruedas@ugr.esmailto [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Walters, Jamie D. [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, UK CB2 1QT (United Kingdom); Orte, Angel [Department of Physical Chemistry, Faculty of Pharmacy, University of Granada, Campus Cartuja, 18071, Granada (Spain); Hall, Elizabeth A.H., E-mail: lisa.hall@biotech.cam.ac.uk [Department of Chemical Engineering and Biotechnology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1QT (United Kingdom)

    2012-11-02

    Highlights: Black-Right-Pointing-Pointer Analytical applications of fluorescent nanoparticles (NPs) in intracellular sensing. Black-Right-Pointing-Pointer Critical review on performance of QDots, metal NPs, silica NPs, and polymer NPs. Black-Right-Pointing-Pointer Highlighted potential of fluorescence lifetime imaging microscopy (FLIM). - Abstract: Fluorescent nanoparticles (NPs), including semiconductor NPs (Quantum Dots), metal NPs, silica NPs, polymer NPs, etc., have been a major focus of research and development during the past decade. The fluorescent nanoparticles show unique chemical and optical properties, such as brighter fluorescence, higher photostability and higher biocompatibility, compared to classical fluorescent organic dyes. Moreover, the nanoparticles can also act as multivalent scaffolds for the realization of supramolecular assemblies, since their high surface to volume ratio allow distinct spatial domains to be functionalized, which can provide a versatile synthetic platform for the implementation of different sensing schemes. Their excellent properties make them one of the most useful tools that chemistry has supplied to biomedical research, enabling the intracellular monitoring of many different species for medical and biological purposes. In this review, we focus on the developments and analytical applications of fluorescent nanoparticles in chemical and biological sensing within the intracellular environment. The review also points out the great potential of fluorescent NPs for fluorescence lifetime imaging microscopy (FLIM). Finally, we also give an overview of the current methods for delivering of fluorescent NPs into cells, where critically examine the benefits and liabilities of each strategy.

  10. Intracellular Cholesterol Trafficking and Impact in Neurodegeneration

    Directory of Open Access Journals (Sweden)

    Fabian Arenas

    2017-11-01

    Full Text Available Cholesterol is a critical component of membrane bilayers where it plays key structural and functional roles by regulating the activity of diverse signaling platforms and pathways. Particularly enriched in brain, cholesterol homeostasis in this organ is singular with respect to other tissues and exhibits a heterogeneous regulation in distinct brain cell populations. Due to the key role of cholesterol in brain physiology and function, alterations in cholesterol homeostasis and levels have been linked to brain diseases and neurodegeneration. In the case of Alzheimer disease (AD, however, this association remains unclear with evidence indicating that either increased or decreased total brain cholesterol levels contribute to this major neurodegenerative disease. Here, rather than analyzing the role of total cholesterol levels in neurodegeneration, we focus on the contribution of intracellular cholesterol pools, particularly in endolysosomes and mitochondria through its trafficking via specialized membrane domains delineated by the contacts between endoplasmic reticulum and mitochondria, in the onset of prevalent neurodegenerative diseases such as AD, Parkinson disease, and Huntington disease as well as in lysosomal disorders like Niemann-Pick type C disease. We dissect molecular events associated with intracellular cholesterol accumulation, especially in mitochondria, an event that results in impaired mitochondrial antioxidant defense and function. A better understanding of the mechanisms involved in the distribution of cholesterol in intracellular compartments may shed light on the role of cholesterol homeostasis disruption in neurodegeneration and may pave the way for specific intervention opportunities.

  11. A bacteriophage endolysin that eliminates intracellular streptococci

    Science.gov (United States)

    Shen, Yang; Barros, Marilia; Vennemann, Tarek; Gallagher, D Travis; Yin, Yizhou; Linden, Sara B; Heselpoth, Ryan D; Spencer, Dennis J; Donovan, David M; Moult, John; Fischetti, Vincent A; Heinrich, Frank; Lösche, Mathias; Nelson, Daniel C

    2016-01-01

    PlyC, a bacteriophage-encoded endolysin, lyses Streptococcus pyogenes (Spy) on contact. Here, we demonstrate that PlyC is a potent agent for controlling intracellular Spy that often underlies refractory infections. We show that the PlyC holoenzyme, mediated by its PlyCB subunit, crosses epithelial cell membranes and clears intracellular Spy in a dose-dependent manner. Quantitative studies using model membranes establish that PlyCB interacts strongly with phosphatidylserine (PS), whereas its interaction with other lipids is weak, suggesting specificity for PS as its cellular receptor. Neutron reflection further substantiates that PlyC penetrates bilayers above a PS threshold concentration. Crystallography and docking studies identify key residues that mediate PlyCB–PS interactions, which are validated by site-directed mutagenesis. This is the first report that a native endolysin can traverse epithelial membranes, thus substantiating the potential of PlyC as an antimicrobial for Spy in the extracellular and intracellular milieu and as a scaffold for engineering other functionalities. DOI: http://dx.doi.org/10.7554/eLife.13152.001 PMID:26978792

  12. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff.

    Science.gov (United States)

    Miller, Melissa A; Byrne, Barbara A; Jang, Spencer S; Dodd, Erin M; Dorfmeier, Elene; Harris, Michael D; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A; Miller, Woutrina A

    2010-01-01

    Although protected for nearly a century, California's sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health.

  13. Enteric bacterial pathogen detection in southern sea otters (Enhydra lutris nereis) is associated with coastal urbanization and freshwater runoff

    Science.gov (United States)

    Miller, Melissa A.; Byrne, Barbara A.; Jang, Spencer S.; Dodd, Erin M.; Dorfmeier, Elene; Harris, Michael D.; Ames, Jack; Paradies, David; Worcester, Karen; Jessup, David A.; Miller, Woutrina A.

    2009-01-01

    Although protected for nearly a century, California’s sea otters have been slow to recover, in part due to exposure to fecally-associated protozoal pathogens like Toxoplasma gondii and Sarcocystis neurona. However, potential impacts from exposure to fecal bacteria have not been systematically explored. Using selective media, we examined feces from live and dead sea otters from California for specific enteric bacterial pathogens (Campylobacter, Salmonella, Clostridium perfringens, C. difficile and Escherichia coli O157:H7), and pathogens endemic to the marine environment (Vibrio cholerae, V. parahaemolyticus and Plesiomonas shigelloides). We evaluated statistical associations between detection of these pathogens in otter feces and demographic or environmental risk factors for otter exposure, and found that dead otters were more likely to test positive for C. perfringens, Campylobacter and V. parahaemolyticus than were live otters. Otters from more urbanized coastlines and areas with high freshwater runoff (near outflows of rivers or streams) were more likely to test positive for one or more of these bacterial pathogens. Other risk factors for bacterial detection in otters included male gender and fecal samples collected during the rainy season when surface runoff is maximal. Similar risk factors were reported in prior studies of pathogen exposure for California otters and their invertebrate prey, suggesting that land-sea transfer and/or facilitation of pathogen survival in degraded coastal marine habitat may be impacting sea otter recovery. Because otters and humans share many of the same foods, our findings may also have implications for human health. PMID:19720009

  14. Intracellular fate of Ureaplasma parvum entrapped by host cellular autophagy.

    Science.gov (United States)

    Nishiumi, Fumiko; Ogawa, Michinaga; Nakura, Yukiko; Hamada, Yusuke; Nakayama, Masahiro; Mitobe, Jiro; Hiraide, Atsushi; Sakai, Norio; Takeuchi, Makoto; Yoshimori, Tamotsu; Yanagihara, Itaru

    2017-06-01

    Genital mycoplasmas, including Ureaplasma spp., are among the smallest human pathogenic bacteria and are associated with preterm birth. Electron microscopic observation of U. parvum showed that these prokaryotes have a regular, spherical shape with a mean diameter of 146 nm. U. parvum was internalized into HeLa cells by clathrin-mediated endocytosis and survived for at least 14 days around the perinuclear region. Intracellular U. parvum reached endosomes in HeLa cells labeled with EEA1, Rab7, and LAMP-1 within 1 to 3 hr. After 3 hr of infection, U. parvum induced the cytosolic accumulation of galectin-3 and was subsequently entrapped by the autophagy marker LC3. However, when using atg7 -/- MEF cells, autophagy was inadequate for the complete elimination of U. parvum in HeLa cells. U. parvum also colocalized with the recycling endosome marker Rab11. Furthermore, the exosomes purified from infected HeLa cell culture medium included U. parvum. In these purified exosomes ureaplasma lipoprotein multiple banded antigen, host cellular annexin A2, CD9, and CD63 were detected. This research has successfully shown that Ureaplasma spp. utilize the host cellular membrane compartments possibly to evade the host immune system. © 2017 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  15. Clinical Toxoplasma gondii, Hammondia heydorni, and Sarcocystis spp. infections in dogs.

    Science.gov (United States)

    Dubey, J P; Ross, A D; Fritz, D

    2003-12-01

    Concurrent infections with coccidians Toxoplasma gondii, Sarcocystis spp., and a Hammondia heydorni-like parasite were identified in tissues of three littermate pups on a Kelpie dog breeding farm in Australia. In total, 20 pups in four litters had died following vaccination with an attenuated distemper virus vaccine. Toxoplasma gondii tachyzoites were identified immunohistochemically in tissues of two dogs. Sarcocystis sp. sporocysts were seen in the intestinal lamina propria of two dogs. Asexual and sexual stages of H. heydorni-like parasite were found in enterocytes of the small intestine of two dogs. Ultrastructural development of schizonts and gamonts of this parasite is described. None of the protozoa in these dogs reacted with antibodies to Neospora caninum. Feeding of uncooked tissue of sheep was considered to be the likely source of infection for these coccidians in dogs.

  16. Toxoplasma gondii coinfection with diseases and parasites in wild rabbits in Scotland.

    Science.gov (United States)

    Mason, Sam; Dubey, J P; Smith, Judith E; Boag, Brian

    2015-09-01

    In wild rabbits (Oryctolagus cuniculus) on an estate in Perthshire, central Scotland, the seroprevalence of Toxoplasma gondii was 18/548 (3·3%). The wild rabbit could be a T. gondii reservoir and it has potential value as a sentinel of T. gondii in environmental substrates. Toxoplasma gondii was associated with female sex (P myxomatosis caused by the virus Myxomatosis cuniculi, the intensity of roundworm eggs, the year or season, rabbit age or distance from farm buildings. Coinfections could have been affected by gestational down regulation of type 1 T helper cells. A sudden influx or release of T. gondii oocysts might have occurred. This is the first report of T. gondii in any wild herbivore in Scotland and also the first report of lapine T. gondii as a coinfection with E. stiedae, M. cuniculi and helminths.

  17. Prevalence of Toxoplasma gondii antibodies and intestinal parasites in stray cats from Nigde, Turkey

    Directory of Open Access Journals (Sweden)

    Bengi Dündar

    2010-01-01

    Full Text Available The prevalence of antibodies to Toxoplasma gondii was investigated by the Sabin-Feldman Dye test (SFDT in 72 stray cats from Nigde, Turkey. A total of 55 (76.4% of the analysed sera had antibodies to T. gondii. The seropositivity of T. gondii was 77.1% in male and 75.7% in female cats (P>0.05. Faeces of these cats were also examined by zinc sulphate flotation method for the presence of parasite oocysts and eggs of other parasites. Two protozoan parasites were identified as Isospora spp. (12.5% and Eimeria spp. (4.1% in cats. Toxoplasma gondii oocysts were not found in any faecal samples analysed. Two parasitic helminth species were observed: Toxocara cati (15.2% and Toxascaris leonina (20.8%. These common ascarids were recorded for the first time in cats from Nigde.

  18. [Advances in researches on mechanism of anti-Toxoplasma Chinese herbal medicine].

    Science.gov (United States)

    Yu, Zhao-Yun; Zhang, Bao-de; Ning, Jun-ya; Wang, Yuan-yuan; Yuan, Wen-ying

    2015-10-01

    Toxoplasma gondii is an opportunity cellular parasite, related to the infection of various animals and human beings and severely impairing agriculture and human health. Because of the complexity of T. gondii life cycle, its different biological characteristics, and multifarious pathogenesis, there are no specific treatment and preventive medicines at present. Chinese herbal medicine can balance "yin-yang" and regulate the immunity and its side-effect is slight. Now, it has been a hot topic of the research on effective and secure medicines in anti-toxoplasmosis. This paper summarizes and analyzes the curative effect and mechanism of anti-Toxoplasma Chinese herbal medicine, such as Scutellaria baicalensis, Inontus obliquus polysaccharide, Radix glycyrrhizae, pumpkin seeds, and Semen arecae.

  19. Response of white mice to inoculation of irradiated organisms of the Toxoplasma strain RH

    International Nuclear Information System (INIS)

    Mas Bakal, P.; Veld, N. in't

    1979-01-01

    Chemoterapeutic agents available for use against toxoplasmosis are usually not suitable for prophylatic purposes because of their toxicity. The observed increasing number of activated latent infections with Toxoplasma, especially in immune suppressed patients, requires that safe techniques are available for use during the patients' regression period. Pretreatment of mice with Toxoplasma killed by irradiation appeared to induce resistance to challenge with virulent organisms. Survival times of six months have been observed to date. Increasing effectiveness was seen after more than one administration. Further investigation into the duration of effective resistance is needed; the question of at which intervals subsequent inoculations should be performed in order to acquire a booster effect, if any, has still to be solved before application to man can be recommended. (orig.) [de

  20. Serological survey of Toxoplasma gondii, Dirofilaria immitis, Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) infections in pet cats in Bangkok and vicinities, Thailand.

    Science.gov (United States)

    Sukhumavasi, Woraporn; Bellosa, Mary L; Lucio-Forster, Araceli; Liotta, Janice L; Lee, Alice C Y; Pornmingmas, Pitcha; Chungpivat, Sudchit; Mohammed, Hussni O; Lorentzen, Leif; Dubey, J P; Bowman, Dwight D

    2012-08-13

    The seroprevalence of Toxoplasma gondii, Dirofilaria immitis (heartworm), feline immunodeficiency virus (FIV) and feline leukemia virus (FeLV) infections was examined using serum or plasma samples from 746 pet cats collected between May and July 2009 from clinics and hospitals located in and around Bangkok, Thailand. The samples were tested for heartworm, FIV, and FeLV using a commercial ELISA. Of the 746 samples, 4.6% (34/746) were positive for heartworm antigen, 24.5% (183/746) had circulating FeLV antigen, and 20.1% (150/746) had antibodies against FIV. In addition, the first 348 submitted samples were tested for T. gondii antibodies using a modified agglutination test (MAT, cut off 1:25); 10.1% (35/348) were seropositive. Of the 348 cats sampled for all four pathogens, 11, 10, and 1 were positive for T. gondii antibodies and FIV antibodies, FeLV antigen, or D. immitis antigen, respectively. Of the 35 T. gondii-seropositive cats, 42.9% (15/35) were co-infected with at least one of the other three pathogens. The presence of antibodies to FIV was significantly associated with both age and gender, while FeLV antigen presence was only associated with age. In the case of FIV, males were twice as likely to be infected as females, and cats over 10 years of age were 13.5 times more likely to be infected than cats less than 1 year of age. FeLV antigen was more common in younger cats, with cats over 10 years of age being 10 times less likely to be FeLV positive than cats under 1 year of age. This is the first survey for these four pathogens affecting feline health in Thailand. Copyright © 2012 Elsevier B.V. All rights reserved.

  1. Arylthiazole antibiotics targeting intracellular methicillin-resistant Staphylococcus aureus (MRSA) that interfere with bacterial cell wall synthesis.

    Science.gov (United States)

    Eid, Islam; Elsebaei, Mohamed M; Mohammad, Haroon; Hagras, Mohamed; Peters, Christine E; Hegazy, Youssef A; Cooper, Bruce; Pogliano, Joe; Pogliano, Kit; Abulkhair, Hamada S; Seleem, Mohamed N; Mayhoub, Abdelrahman S

    2017-10-20

    The promising antibacterial potency of arylthiazole antibiotics is offset by their limited activity against intracellular bacteria (namely methicillin-resistant Staphylococcus aureus (MRSA)), similar to many clinically-approved antibiotics. The failure to target these hidden pathogens is due to the compounds' lack of proper characteristics to accumulate intracellularly. Fine tuning of the size and polar-surface-area of the linking heteroaromatic ring provided a new series of 5-thiazolylarylthiazoles with balanced properties that allow them to sufficiently cross and accumulate inside macrophages infected with MRSA. The most promising compound 4i exhibited rapid bactericidal activity, good metabolic stability and produced over 80% reduction of intracellular MRSA in infected macrophages. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  2. Comparison of Eight Cell-Free Media for Maintenance of Toxoplasma gondii Tachyzoites

    Directory of Open Access Journals (Sweden)

    Hamed KALANI

    2016-03-01

    Full Text Available Background: Toxoplasmosis is considered as one of the most common infectious diseases caused by the protozoan parasite Toxoplasma gondii. Tachyzoite is the main form of Toxoplasma and continuously is maintained in cell culture or injected into the mice peritoneal cavity. This study was designed to evaluate the survival rate of RH strain of T. gondii tachyzoites in different cell free, nutrient and biological media at different temperatures.Methods: This experimental study was performed at the Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran, in 2010. One ml of each solution including hypotonic saline (0.3%, normal saline (0.85%, RPMI-1640 (RPMI, RPMI with 10% fetal bovine serum (FBS, RPMI with 20% FBS, ovine hydatid cyst fluid, pasteurized milk of cow, and phosphate buffered saline (PBS along with 4×104 T. gondii tachyzoites were added to plate wells and incubated in 4 °C, 22 °C, 37 °C, and 37 °C under 5% CO2. The survival rate and viability as­sessment of parasites were performed daily and the results were analyzed using Univariate tests.Result: Tachyzoites survival rate in PBS (4 °C and normal saline (4 °C were con­siderably high, compared to other solutions in different conditions (P<0.001. The best temperature for Toxoplasma maintenance was 4 °C (P<0.001.Conclusion: This study introduces two available and economical solutions, PBS (4 °C and normal saline (4 °C media, for maintenance of Toxoplasma tachyzoites as appropriate choice media for a noticeable period of time (11 days in vitro.

  3. Epidemiology and pathology of Toxoplasma gondii in free-ranging California sea lions (Zalophus californianus)

    OpenAIRE

    Carlson-Bremer, D; Colegrove, KM; Gulland, FMD; Conrad, PA; Mazet, JAK; Johnson, CK

    2015-01-01

    © Wildlife Disease Association 2015. The coccidian parasite Toxoplasma gondii infects humans and warm-blooded animals worldwide. The ecology of this parasite in marine systems is poorly understood, although many marine mammals are infected and susceptible to clinical toxoplasmosis. We summarized the lesions associated with T. gondii infection in the California sea lion (Zalophus californianus) population and investigated the prevalence of and risk factors associated with T. gondii exposure, a...

  4. Low titer of antibody against Toxoplasma gondii may be related to resistant to cancer

    OpenAIRE

    Maryam Sharafi Seyedeh; Salehi Nahid; Mortazavi Nahid; Danesh Pour Shima; Yousefi Morteza; Yousofi Darani Hossein

    2015-01-01

    Context: Toxoplasma gondii is a protozoan parasite with a world-wide distribution. However, the majority of infected cases remain symptomless. There are raising scientific evidences indicating that parasitic infections induce antitumor activity against certain types of cancers. The inhibitory effect of T. gondii on cancer growth has also been shown in cell culture and mouse model. Aims: Considering the anti-tumor effect of this parasite, in this study the relationship between low titer of ...

  5. Datation de l'infection a Toxoplasma gondii chez 128 femmes ...

    African Journals Online (AJOL)

    L'utilisation de ce test dans les laboratoires de biologie médicale au Togo pourrait contribuer à améliorer la prise charge adéquate des femmes enceintes au Togo. Mots clés: Toxoplasmose, sérologie, test d'avidité, femmes enceintes, Togo. English Title: Datation of Toxoplasma gondii infection among pregnant women in a ...

  6. Seroprevalence of Toxoplasma gondii in free-ranging and feral cats on Amami Oshima Island, Japan

    OpenAIRE

    MATSUU, Aya; YOKOTA, Shin-ichi; ITO, Keiko; MASATANI, Tatsunori

    2017-01-01

    On Amami Oshima Island, free-ranging and feral cats are harmful to wildlife populations. In this study, the seroprevalence of Toxoplasma gondii in these cats was examined using a newly developed Gaussia luciferase immunoprecipitation system assay. Of 1,363 cats, 123 cats (9.0%) was positive for T. gondii. The prevalence was significantly different in different areas; among cats in the rural area, where many wild animals live, including endangered species, T. gondii infection was more prevalen...

  7. Chronic Toxoplasma gondii in Nurr1-Null Heterozygous Mice Exacerbates Elevated Open Field Activity

    OpenAIRE

    Eells, Jeffrey B.; Varela-Stokes, Andrea; Guo-Ross, Shirley X.; Kummari, Evangel; Smith, Holly M.; Cox, Erin; Lindsay, David S.

    2015-01-01

    Latent infection with Toxoplasma gondii is common in humans (approximately 30% of the global population) and is a significant risk factor for schizophrenia. Since prevalence of T. gondii infection is far greater than prevalence of schizophrenia (0.5-1%), genetic risk factors are likely also necessary to contribute to schizophrenia. To test this concept in an animal model, Nurr1-null heterozygous (+/-) mice and wild-type (+/+) mice were evaluate using an emergence test, activity in an open fie...

  8. Toxoplasma Infection in Schizophrenia Patients: A Comparative Study with Control Group

    OpenAIRE

    Alipour, A; Shojaee, S; Mohebali, M; Tehranidoost, M; Abdi Masoleh, F; Keshavarz, H

    2011-01-01

    Background: Schizophrenia is a serious, chronic, and often debilitating neuropsychiatric disor­der. Its causes are still poorly understood. Besides genetic and non-genetic (environmental) fac­tors are thought to be important as the cause of the structural and functional deficits that character­ize schizophrenia. This study aimed to compare Toxoplasma gondii infection between schizo­phrenia patients and non-schizophrenia individuals as control group.Methods: A case-control study was designed i...

  9. Loop-mediated isothermal amplification (LAMP): Early detection of Toxoplasma gondii infection in mice

    OpenAIRE

    Kong, Qing-Ming; Lu, Shao-Hong; Tong, Qun-Bo; Lou, Di; Chen, Rui; Zheng, Bin; Kumagai, Takashi; Wen, Li-Yong; Ohta, Nobuo; Zhou, Xiao-Nong

    2012-01-01

    Abstract Background Toxoplasmosis is a widespread zoonotic parasitic disease that occurs in both animals and humans. Traditional molecular assays are often difficult to perform, especially for the early diagnosis of Toxoplasma gondii infections. Here, we established a novel loop-mediated isothermal amplification targeting the 529 bp repeat element (529 bp-LAMP) to detect T. gondii DNA in blood samples of experimental mice infected with tachyzoites of the RH strain. Findings The assay was perf...

  10. ELISA-seroprevalence of Toxoplasma gondii in draught horses in Greater Cairo, Egypt.

    Science.gov (United States)

    Haridy, Fouad M; Shoukry, Nahla M; Hassan, Aly Awad; Morsy, Tosson A

    2009-12-01

    Toxoplasma gondii is one of the important zoonotic parasites of worldwide. In this paper the seroprevalence of T. gondii in draught horses (3-15 years) including 90 males and 10 females in the first half of the year 2009 was studied. The result showed that the overall ELISA-T. gondii antibodies were 25% of the horses in Greater Cairo, 50% (females) and 22.2% (males).

  11. The Effect of Toxoplasma gondii on Animal Behavior: Playing Cat and Mouse

    OpenAIRE

    Webster, Joanne P.

    2007-01-01

    A convincing body of evidence now exists to indicate that the ubiquitous protozoan Toxoplasma gondii can cause permanent behavioral changes in its host, even as a consequence of adult-acquired latent infection. Such behavioral alterations appear to be the product of strong selective pressures for the parasite to enhance transmission from its intermediate host reservoir, primarily rodent, to its feline definitive host, wherein sexual reproduction can occur and the life cycle completed. This ar...

  12. Screening and identification of novel B cell epitopes of Toxoplasma gondii SAG1

    OpenAIRE

    Wang, Yanhua; Wang, Guangxiang; Zhang, Delin; Yin, Hong; Wang, Meng

    2013-01-01

    Background The identification of protein epitopes is useful for diagnostic purposes and for the development of peptide vaccines. In this study, the epitopes of Toxoplasma gondii SAG1 were identified using synthetic peptide techniques with the aid of bioinformatics. Findings Eleven peptides derived from T. gondii SAG1 were assessed by ELISA using pig sera from different time points after infection. Four (PS4, PS6, PS10 and PS11), out of the eleven peptides tested were recognized by all sera. T...

  13. Feast or famine: the host-pathogen battle over amino acids.

    Science.gov (United States)

    Zhang, Yanjia J; Rubin, Eric J

    2013-07-01

    Intracellular bacterial pathogens often rely on their hosts for essential nutrients. Host cells, in turn, attempt to limit nutrient availability, using starvation as a mechanism of innate immunity. Here we discuss both host mechanisms of amino acid starvation and the diverse adaptations of pathogens to their nutrient-deprived environments. These processes provide both key insights into immune subversion and new targets for drug development. © 2013 John Wiley & Sons Ltd.

  14. Extracts against Various Pathogens

    Directory of Open Access Journals (Sweden)

    Ritika Chauhan

    2013-07-01

    The present study shows that tested lichen Parmotrema sp. extracts demonstrated a strong antimicrobial effect. That suggests the active components from methanol extracts of the investigated lichen Parmotrema sp. can be used as natural antimicrobial agent against pathogens.

  15. Evolution of microbial pathogens

    National Research Council Canada - National Science Library

    DiRita, Victor J; Seifert, H. Steven

    2006-01-01

    ... A. Hogan vvi ■ CONTENTS 8. Evolution of Pathogens in Soil Rachel Muir and Man-Wah Tan / 131 9. Experimental Models of Symbiotic Host-Microbial Relationships: Understanding the Underpinnings of ...

  16. Indicators for waterborne pathogens

    National Research Council Canada - National Science Library

    Committee on Indicators for Waterborne Pathogens, National Research Council

    2004-01-01

    ... not practical or feasible to monitor for the complete spectrum of microorganisms that may occur in water, and many known pathogens are difficult to detect directly and reliably in water samples.Â...

  17. Host–Pathogen Interactions

    NARCIS (Netherlands)

    Smits, M.A.; Schokker, D.J.

    2011-01-01

    The outcome of an infection is determined by numerous interactions between hosts and pathogens occurring at many different biological levels, ranging from molecule to population. To develop new control strategies for infectious diseases in livestock species, appropriate methodologies are needed

  18. Detection of Toxoplasma gondii oocysts in different water resources by Loop Mediated Isothermal Amplification (LAMP).

    Science.gov (United States)

    Gallas-Lindemann, Carmen; Sotiriadou, Isaia; Mahmoodi, Mohammad Reza; Karanis, Panagiotis

    2013-02-01

    Human toxoplasmosis is potentially contracted due to consumption of contaminated drinking water and represents an increasing public health risk worldwide. Toxoplasma gondii oocysts can be resistant to standard disinfection processes, including UV radiation. Increased awareness of the risk of waterborne toxoplasmosis outbreaks has led to an increase in research interest in the detection of oocysts in environmental water systems. Ninety-five environmental water samples from the Lower Rhine area in Germany have been included in the study and examined for the presence of Toxoplasma. Water samples were filtered or flocculated by aluminum sulfate and purified by sucrose density gradient. DNA was then extracted, and the DNA samples were then examined by LAMP analysis. T. gondii DNA was detected in eight out of 83 (9.6%) influent and effluent samples obtained from wastewater treatment plants. All samples (n=12) from the surface, ground, raw and tap waters tested negative. The purpose of this work was to investigate the occurrence and distribution of Toxoplasma oocysts on the Lower Rhine in Germany. Our study provides evidence that the assay is a sensitive, specific, rapid and cost effective method for the detection of T. gondii and is useful for both the investigations of cases of waterborne outbreaks and for identifying the source of contamination. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. RNG1 is a Late Marker of the Apical Polar Ring in Toxoplasma gondii

    Science.gov (United States)

    Tran, Johnson Q.; de Leon, Jessica C.; Li, Catherine; Huynh, My-Hang; Beatty, Wandy; Morrissette, Naomi S.

    2010-01-01

    The asexually proliferating stages of apicomplexan parasites cause acute symptoms of diseases such as malaria, cryptosporidiosis and toxoplasmosis. These stages are characterized by the presence of two independent microtubule organizing centers (MTOCs). Centrioles are found at the poles of the intranuclear spindle. The apical polar ring (APR), a MTOC unique to apicomplexans, organizes subpellicular microtubules which impose cell shape and apical polarity on these protozoa. Here we describe the characteristics of a novel protein that localizes to the APR of Toxoplasma gondii which we have named ring-1 (RNG1). There are related RNG1 proteins in Neospora caninum and Sarcocystis neurona but no obvious homologs in Plasmodium spp., Cryptosporidium spp. or Babesia spp. RNG1 is a small, low-complexity, detergent-insoluble protein that assembles at the APR very late in the process of daughter parasite replication. We were unable to knock-out the RNG1 gene, suggesting that its gene product is essential. Tagged RNG1 lines have also allowed us to visualize the APR during growth of Toxoplasma in the microtubule-disrupting drug oryzalin. Oryzalin inhibits nuclear division and cytokinesis although Toxoplasma growth continues, and similar to earlier observations of unchecked centriole duplication in oryzalin-treated parasites, the APR continues to duplicate during aberrant parasite growth. PMID:20658557

  20. Optimization of dipeptidic inhibitors of cathepsin L for improved Toxoplasma gondii selectivity and CNS permeability.

    Science.gov (United States)

    Zwicker, Jeffery D; Diaz, Nicolas A; Guerra, Alfredo J; Kirchhoff, Paul D; Wen, Bo; Sun, Duxin; Carruthers, Vern B; Larsen, Scott D

    2018-06-01

    The neurotropic protozoan Toxoplasma gondii is the second leading cause of death due to foodborne illness in the US, and has been designated as one of five neglected parasitic infections by the Center for Disease Control and Prevention. Currently, no treatment options exist for the chronic dormant-phase Toxoplasma infection in the central nervous system (CNS). T. gondii cathepsin L (TgCPL) has recently been implicated as a novel viable target for the treatment of chronic toxoplasmosis. In this study, we report the first body of SAR work aimed at developing potent inhibitors of TgCPL with selectivity vs the human cathepsin L. Starting from a known inhibitor of human cathepsin L, and guided by structure-based design, we were able to modulate the selectivity for Toxoplasma vs human CPL by nearly 50-fold while modifying physiochemical properties to be more favorable for metabolic stability and CNS penetrance. The overall potency of our inhibitors towards TgCPL was improved from 2 μM to as low as 110 nM and we successfully demonstrated that an optimized analog 18b is capable of crossing the BBB (0.5 brain/plasma). This work is an important first step toward development of a CNS-penetrant probe to validate TgCPL as a feasible target for the treatment of chronic toxoplasmosis. Copyright © 2018 Elsevier Ltd. All rights reserved.