Prematurity and Low Birth Weight did not Correlate with Anti-Toxoplasma gondii Maternal Serum Profiles--a Brazilian Report

PLoS One. 2015 Jul 20;10(7):e0132719. doi: 10.1371/journal.pone.0132719. eCollection 2015.

 

Fochi MM¹, Baring S², Spegiorin LC³, Vaz-Oliani DC⁴, Galão EA⁴, Oliani AH⁵, de Mattos LC¹, de Mattos CC¹.

 

Gestational Toxoplasma gondii infection is considered a major risk factor for miscarriage, prematurity and low birth weight in animals. However, studies focusing on this topic in humans are scarce. The objective of this study is to determine whether anti-Toxoplasma gondii maternal serum profiles correlate prematurity and low birth weight in humans. The study examined 213 pregnant women seen at the High-Risk Pregnancy Hospital de Base, São José do Rio Preto, São Paulo, Brazil. All serological profiles (IgM-/IgG+; IgM-/IgG-; IgM+/IgG+) were determined by ELISA commercial kits. Maternal age, gestational age and weight of the newborn at birth were collected and recorded in the Statement of Live Birth. Prematurity was defined as gestational age less than 37 weeks and low birth weight less than 2499 grams. The t-test was used to compare values (p less 0.05). The mean maternal age was 27.6±6.6 years. Overall, 56.3% (120/213) of the women studied were IgM-/IgG+, 36.2% (77/213) were IgM-/IgG- and 7.5% (16/213) were IgM+/IgG+. The average age of the women with serological profile IgM+/IgG+ (22.3±3.9 years) was different from women with the profile IgM-/IgG+ (27.9±6.7 years, p = 0.0011) and IgM-/IgG- (27.9±6.4 years, p = 0.0012). There was no statistically significant difference between the different serological profiles in relation to prematurity (p = 0.6742) and low birth weight (p = 0.7186). The results showed that prematurity and low birth weight did not correlate with anti-Toxoplasma gondii maternal serum profiles.

PMID:

26192182

[PubMed - in process]

PMCID:

PMC4508015

Qualitative Assessment for Toxoplasma gondii Exposure Risk Associated with Meat Products in the United States

J Food Prot. 2015 Dec;78(12):2207-19. doi: 10.4315/0362-028X.JFP-15-270.

 

Guo M¹, Buchanan RL², Dubey JP³, Hill DE³, Lambertini E⁴, Ying Y¹, Gamble HR⁵, Jones JL⁶, Pradhan AK⁷.

 

Toxoplasma gondii is a global protozoan parasite capable of infecting most warm-blooded animals. Although healthy adult humans generally have no symptoms, severe illness does occur in certain groups, including congenitally infected fetuses and newborns, immunocompromised individuals including transplant patients. Epidemiological studies have demonstrated that consumption of raw or undercooked meat products is one of the major sources of infection with T. gondii. The goal of this study was to develop a framework to qualitatively estimate the exposure risk to T. gondii from various meat products consumed in the United States. Risk estimates of various meats were analyzed by a farm-to-retail qualitative assessment that included evaluation of farm, abattoir, storage and transportation, meat processing, packaging, and retail modules. It was found that exposure risks associated with meats from free-range chickens, nonconfinement-raised pigs, goats, and lamb are higher than those from confinement-raised pigs, cattle, and caged chickens. For fresh meat products, risk at the retail level was similar to that at the farm level unless meats had been frozen or moisture enhanced. Our results showed that meat processing, such as salting, freezing, commercial hot air drying, long fermentation times, hot smoking, and cooking, are able to reduce T. gondii levels in meat products. whereas nitrite and/or nitrate, spice, low pH, and cold storage have no effect on the viability of T. gondii tissue cysts. Raw-fermented sausage, cured raw meat, meat that is not hot-air dried, and fresh processed meat were associated with higher exposure risks compared with cooked meat and frozen meat. This study provides a reference for meat management control programs to determine critical control points and serves as the foundation for future quantitative risk assessments.

PMID:

26613916

[PubMed - in process]

The IL-12 Response of Primary Human Dendritic Cells and Monocytes to Toxoplasma gondii Is Stimulated by Phagocytosis of Live Parasites Rather Than Host Cell Invasion

J Immunol. 2015 Nov 23. pii: 1501558. [Epub ahead of print]

Tosh KW1, Mittereder L2, Bonne-Annee S3, Hieny S2, Nutman TB3, Singer SM4, Sher A2, Jankovic D5.

Author information

Abstract

As a major natural host for Toxoplasma gondii, the mouse is widely used for the study of the immune response to this medically important protozoan parasite. However, murine innate recognition of toxoplasma depends on the interaction of parasite profilin with TLR11 and TLR12, two receptors that are functionally absent in humans. This raises the question of how human cells detect and respond to T. gondii. In this study, we show that primary monocytes and dendritic cells from peripheral blood of healthy donors produce IL-12 and other proinflammatory cytokines when exposed to toxoplasma tachyzoites. Cell fractionation studies determined that IL-12 and TNF-α secretion is limited to CD16+ monocytes and the CD1c+ subset of dendritic cells. In direct contrast to their murine counterparts, human myeloid cells fail to respond to soluble tachyzoite extracts and instead require contact with live parasites. Importantly, we found that tachyzoite phagocytosis, but not host cell invasion, is required for cytokine induction. Together these findings identify CD16+ monocytes and CD1c+ dendritic cells as the major myeloid subsets in human blood-producing innate cytokines in response to T. gondii and demonstrate an unappreciated requirement for phagocytosis of live parasites in that process. This form of pathogen sensing is distinct from that used by mice, possibly reflecting a direct involvement of rodents and not humans in the parasite life cycle.

Copyright © 2015 by The American Association of Immunologists, Inc.

PMID:

 

26597011

 

[PubMed - as supplied by publisher]

Combined Toxoplasma gondii seropositivity and high blood kynurenine - Linked with nonfatal suicidal self-directed violence in patients with schizophrenia

J Psychiatr Res. 2015 Oct 9;72:74-81. doi: 10.1016/j.jpsychires.2015.10.002. [Epub ahead of print]

Okusaga O1, Duncan E2, Langenberg P3, Brundin L4, Fuchs D5, Groer MW6, Giegling I7, Stearns-Yoder KA8, Hartmann AM7, Konte B7, Friedl M7, Brenner LA9, Lowry CA10, Rujescu D7, Postolache TT11.

Author information

Abstract

Toxoplasma gondii (T. gondii) chronic infection and elevated kynurenine (KYN) levels have been individually associated with non-fatal suicidal self-directed violence (NF-SSDV). We aimed to test the hypothesis that the association between T. gondii seropositivity and history of NF-SSDV would be stronger in schizophrenia patients with high plasma KYN levels than in those with lower KYN levels. We measured anti-T. gondii IgG antibodies and plasma KYN in 950 patients with schizophrenia, and used logistic regression to evaluate the relationship between NF-SSDV and KYN in patients who were either seropositive or seronegative for T. gondii. For those with KYN levels in the upper 25th percentile, the unadjusted odds ratio for the association between NF-SSDV history and KYN in T. gondii seropositive patients was 1.63 (95% CI 1.01 to 2.66), p = 0.048; the adjusted odds ratio was 1.95 (95% CI 1.15 to 3.30), p = 0.014. Plasma KYN was not associated with a history of NF-SSDV in T. gondii seronegative patients. The results suggest that T. gondii and KYN may have a nonlinear cumulative effect on the risk of NF-SSDV among those with schizophrenia. If confirmed by future longitudinal studies, this result is expected to have both theoretical and clinical implications for the prevention and treatment of suicidal behavior.

Published by Elsevier Ltd.

KEYWORDS: 

Kynurenine; Non-fatal suicidal self-directed violence; Schizophrenia; Toxoplasma gondii

PMID:

 

26594873

 

[PubMed - as supplied by publisher]

Diversity of extracellular proteins during the transition from the 'proto-apicomplexan' alveolates to the apicomplexan obligate parasites

Parasitology. 2015 Nov 20:1-17. [Epub ahead of print]

Templeton TJ1, Pain A2.

Author information

Abstract

The recent completion of high-coverage draft genome sequences for several alveolate protozoans - namely, the chromerids, Chromera velia and Vitrella brassicaformis; the perkinsid Perkinsus marinus; the apicomplexan, Gregarina niphandrodes, as well as high coverage transcriptome sequence information for several colpodellids, allows for new genome-scale comparisons across a rich landscape of apicomplexans and other alveolates. Genome annotations can now be used to help interpret fine ultrastructure and cell biology, and guide new studies to describe a variety of alveolate life strategies, such as symbiosis or free living, predation, and obligate intracellular parasitism, as well to provide foundations to dissect the evolutionary transitions between these niches. This review focuses on the attempt to identify extracellular proteins which might mediate the physical interface of cell-cell interactions within the above life strategies, aided by annotation of the repertoires of predicted surface and secreted proteins encoded within alveolate genomes. In particular, we discuss what descriptions of the predicted extracellular proteomes reveal regarding a hypothetical last common ancestor of a pre-apicomplexan alveolate - guided by ultrastructure, life strategies and phylogenetic relationships - in an attempt to understand the evolution of obligate parasitism in apicomplexans.

KEYWORDS: 

Chromera ; Colpodella ; Cryptosporidium ; Gregarina ; Perkinsus ; Plasmodium ; Toxoplasma ; Vitrella ; Alveolata; Apicomplexa

PMID:

 

26585326

 

[PubMed - as supplied by publisher]

Identification of Direct Kinase Substrates Using Analogue-Sensitive Alleles

Methods Mol Biol. 2016;1355:71-84. doi: 10.1007/978-1-4939-3049-4_5.

Rothenberg DA1,2, Gordon EA1,2, White FM1,2, Lourido S3.

Author information

Abstract

Identifying the substrates of protein kinases remains a major obstacle in the elucidation of eukaryotic signaling pathways. Promiscuity among kinases and their substrates coupled with the extraordinary plasticity of phosphorylation networks renders traditional genetic approaches or small-molecule inhibitors problematic when trying to determine the direct substrates of an individual kinase. Here we describe methods to label, enrich, and identify the direct substrates of analogue-sensitive kinases by exploiting their steric complementarity to artificial ATP analogues. Using calcium-dependent protein kinases of Toxoplasma gondii as a model for these approaches, this protocol brings together numerous advances that enable labeling of kinase targets in semi-permeabilized cells, quantification of direct labeling over background, and highly specific enrichment of targeted phosphopeptides. 

KEYWORDS: 

AS kinase; IMAC; LC MS/MS; Quantitative analysis; SILAC; Toxoplasmosis

PMID:

 

26584919

 

[PubMed - in process]

An aspartyl protease defines a novel pathway for export of Toxoplasma proteins into the host cell

Elife. 2015 Nov 18;4. pii: e10809. doi: 10.7554/eLife.10809. [Epub ahead of print]

Coffey MJ1, Sleebs BE1, Uboldi AD1, Garnham AL1, Franco M2, Marino ND2, Panas MW2, Ferguson DJ3, Enciso M4, O'Neill MT1, Lopaticki S1, Stewart RJ1, Dewson G1, Smyth GK1, Smith BJ4, Masters SL1, Boothroyd JC2, Boddey JA1, Tonkin CJ5.

Author information

Abstract

Infection by Toxoplasma gondii leads to massive changes to the host cell. Here we identify a novel host cell effector export pathway, which requires the Golgi-resident Aspartyl Protease 5 (ASP5). We demonstrate that ASP5 cleaves a highly constrained amino acid motif that has similarity to the PEXEL-motif of Plasmodium parasites. We show that ASP5 matures substrates at both the N- and C-terminal ends of proteins and also controls trafficking of effectors without this motif. Furthermore, ASP5 controls establishment of the nanotubular network and is required for the efficient recruitment of host mitochondria to the vacuole. Assessment of host gene expression reveals that the ASP5-dependent pathway influences thousands of the transcriptional changes that Toxoplasma imparts on its host cell. All these changes result in attenuation of virulence of Δasp5 tachyzoites in vivo. This work characterizes the first identified machinery required for export of Toxoplasma effectors into the infected host cell.

KEYWORDS: 

infectious disease; microbiology

PMID:

 

26576949

 

[PubMed - as supplied by publisher] 

Vaccination with Recombinant Microneme Proteins Confers Protection against Experimental Toxoplasmosis in Mice

PLoS One. 2015 Nov 17;10(11):e0143087. doi: 10.1371/journal.pone.0143087.

Pinzan CF1, Sardinha-Silva A1, Almeida F1, Lai L2, Lopes CD1, Lourenço EV3, Panunto-Castelo A4, Matthews S2, Roque-Barreira MC1.

Author information

Abstract

Toxoplasmosis, a zoonotic disease caused by Toxoplasma gondii, is an important public health problem and veterinary concern. Although there is no vaccine for human toxoplasmosis, many attempts have been made to develop one. Promising vaccine candidates utilize proteins, or their genes, from microneme organelle of T. gondii that are involved in the initial stages of host cell invasion by the parasite. In the present study, we used different recombinant microneme proteins (TgMIC1, TgMIC4, or TgMIC6) or combinations of these proteins (TgMIC1-4 and TgMIC1-4-6) to evaluate the immune response and protection against experimental toxoplasmosis in C57BL/6 mice. Vaccination with recombinant TgMIC1, TgMIC4, or TgMIC6 alone conferred partial protection, as demonstrated by reduced brain cyst burden and mortality rates after challenge. Immunization with TgMIC1-4 or TgMIC1-4-6 vaccines provided the most effective protection, since 70% and 80% of mice, respectively, survived to the acute phase of infection. In addition, these vaccinated mice, in comparison to non-vaccinated ones, showed reduced parasite burden by 59% and 68%, respectively. The protective effect was related to the cellular and humoral immune responses induced by vaccination and included the release of Th1 cytokines IFN-γ and IL-12, antigen-stimulated spleen cell proliferation, and production of antigen-specific serum antibodies. Our results demonstrate that microneme proteins are potential vaccines against T. gondii, since their inoculation prevents or decreases the deleterious effects of the infection.

PMID:

 

26575028

 

[PubMed - as supplied by publisher]

Phosphorylation of αSNAP is required for secretory organelle biogenesis in Toxoplasma gondii

Traffic. 2015 Nov 14. doi: 10.1111/tra.12348. [Epub ahead of print]

Stewart RJ1,2, Ferguson DJ3, Whitehead L1, Bradin CH1, Wu HJ1,2, Tonkin CJ1,2.

Author information

Abstract

Upon infection apicomplexan parasites quickly invade host cells and begin a replicative cycle rapidly increasing in number over a short period of time, leading to tissue lysis and disease. The secretory pathway of these highly polarised protozoan parasites tightly controls, in time and space, the biogenesis of specialised structures and organelles required for invasion and intracellular survival. In other systems regulation of protein trafficking can occur by phosphorylation of vesicle fusion machinery. Previously, we have shown that Toxoplasma gondii αSNAP- a protein that controls the disassembly of cis-SNARE complexes- is phosphorylated. Here we show that this post-translational modification is required for the correct function of αSNAP in controlling secretory traffic. We demonstrate that during intracellular development conditional expression of a non-phosphorylatable form of αSNAP results in Golgi fragmentation and vesiculation of all downstream secretory organelles. In addition we show that the vestigial plastid (termed apicoplast), although reported not to be reliant on Golgi trafficking for biogenesis, is also affected upon overexpression of αSNAP and is much more sensitive to the levels of this protein than targeting to other organelles. This work highlights the importance of αSNAP and its phosphorylation in Toxoplasma organelle biogenesis and exposes a hereto-unexplored mechanism of regulation of vesicle fusion during secretory pathway trafficking in apicomplexan parasites.

This article is protected by copyright. All rights reserved.

KEYWORDS: 

organelle biogenesis; phosphorylation; trafficking; αSNAP

PMID:

 

26566590

 

[PubMed - as supplied by publisher] 

The Ubiquitin Proteome of Toxoplasma gondii Reveals Roles for Protein Ubiquitination in Cell-Cycle Transitions

Cell Host Microbe. 2015 Nov 11;18(5):621-33. doi: 10.1016/j.chom.2015.10.014.

 

Silmon de Monerri NC¹, Yakubu RR¹, Chen AL², Bradley PJ², Nieves E³, Weiss LM⁴, Kim K⁵.

 

Protein ubiquitination plays key roles in protein turnover, cellular signaling, and intracellular transport. The genome of Toxoplasma gondii encodes ubiquitination machinery, but the roles of this posttranslational modification (PTM) are unknown. To examine the prevalence and function of ubiquitination in T. gondii, we mapped the ubiquitin proteome of tachyzoites. Over 500 ubiquitin-modified proteins, with almost 1,000 sites, were identified on proteins with diverse localizations and functions. Enrichment analysis demonstrated that 35% of ubiquitinated proteins are cell-cycle regulated. Unexpectedly, most classic cell-cycle regulators conserved in T. gondii were not detected in the ubiquitinome. Furthermore, many ubiquitinated proteins localize to the cytoskeleton and inner membrane complex, a structure beneath the plasma membrane facilitating division and host invasion. Comparing the ubiquitinome with other PTM proteomes reveals waves of PTM enrichment during the cell cycle. Thus, T. gondii PTMs are implicated as critical regulators of cell division and cell-cycle transitions.
Copyright © 2015 Elsevier Inc. All rights reserved.

PMID:

26567513

[PubMed - in process]

Toxoplasma gondii: history and diagnostic test development

Anim Health Res Rev. 2015 Nov 16:1-13. [Epub ahead of print]

 

Wyrosdick HM¹, Schaefer JJ¹.

 

Toxoplasma gondii is a protozoa that causes toxoplasmosis in people and other animals. It is considered one of the most common parasitic infections in the world due to its impressive range of hosts, widespread environmental contamination and the diverse means by which animals can be infected. Despite its ubiquity and numerous ongoing research efforts into both its basic biology and clinical management, many aspects of diagnosis and management of this disease are poorly understood. The range of diagnostic options that is available for veterinary diagnostic investigators are notably more limited than those available to medical diagnosticians, making accurate interpretation of each test result critical. The current review joins other reviews on the parasite with a particular emphasis on the history and continued development of diagnostic tests that are useful for veterinary diagnostic investigations. An understanding of the strengths and shortcomings of current diagnostic techniques will assist veterinary and public health officials in formulating effective treatment and control strategies in diverse animal populations.

KEYWORDS:

Toxoplasma gondii ; PCR; diagnostic test development; serology; toxoplasmosis; veterinary diagnostic investigation

PMID:

26568360

[PubMed - as supplied by publisher]

Analysis of miRNA expression profiling in mouse spleen affected by acute Toxoplasma gondii infection

Infect Genet Evol. 2015 Nov 10. pii: S1567-1348(15)30035-6. doi: 10.1016/j.meegid.2015.11.005. [Epub ahead of print]

 

He JJ¹, Ma J², Wang JL¹, Xu MJ³, Zhu XQ⁴.

 

Toxoplasma gondii is a worldwide prevalent pathogen that infects most of the warm-blood vertebrates. To investigate the regulation network of splenic miRNAs altered by acute infection with T. gondii, we herein investigated the changes of miRNA profile in mouse spleen via next generation sequencing and bioinformatics analysis. A total of 379 miRNAs was identified, 131 miRNAs of them were differentially expressed (including 97 upregulated and 34 downregulated miRNAs). 48 differentially expressed miRNAs had validated targets in the miRWalk2.0 database. Gene Ontology (GO) enrichment analysis revealed that the validated targets of differently expressed miRNAs were significantly enriched in gene transcription regulation. It suggested that T. gondii can modulate host gene expression through targeting to trans-regulation factors. The genes involved in apoptosis or anti-apoptosis were both targeted by differentially expressed miRNAs. The change of power balance between the miRNAs targeting host apoptosis genes and those regulating host anti-apoptosis genes contributes to the fate of host apoptosis process. Twelve pathways were significantly enriched in KEGG analysis with most of them being cancer related, including pathways in cancer, pancreatic cancer, colorectal cancer, axon guidance, MAPK signaling pathway, focal adhesion, chronic myeloid leukemia, renal cell carcinoma, prostate cancer, glioma, regulation of actin cytoskeleton, and Wnt signaling pathway. Our study showed a changed miRNA regulation network in mouse spleen infected by T. gondii. These findings will be helpful for better understanding of miRNA regulation network in host-T. gondii interaction, revealing the relationship among T. gondii infection, gene regulation, apoptosis and cancer process alterations in infected spleen.
Copyright © 2015. Published by Elsevier B.V.

KEYWORDS:

MicroRNA (miRNA); Mouse; Spleen; Toxoplasma gondii

PMID:

26569573

[PubMed - as supplied by publisher]

Phosphatidylthreonine and Lipid-Mediated Control of Parasite Virulence

PLoS Biol. 2015 Nov 13;13(11):e1002288. doi: 10.1371/journal.pbio.1002288. eCollection 2015.

 

Arroyo-Olarte RD¹, Brouwers JF², Kuchipudi A¹, Helms JB², Biswas A³, Dunay IR³, Lucius R¹, Gupta N^1,4.

 

The major membrane phospholipid classes, described thus far, include phosphatidylcholine (PtdCho), phosphatidylethanolamine (PtdEtn), phosphatidylserine (PtdSer), and phosphatidylinositol (PtdIns). Here, we demonstrate the natural occurrence and genetic origin of an exclusive and rather abundant lipid, phosphatidylthreonine (PtdThr), in a common eukaryotic model parasite, Toxoplasma gondii. The parasite expresses a novel enzyme PtdThr synthase (TgPTS) to produce this lipid in its endoplasmic reticulum. Genetic disruption of TgPTS abrogates de novo synthesis of PtdThr and impairs the lytic cycle and virulence of T. gondii. The observed phenotype is caused by a reduced gliding motility, which blights the parasite egress and ensuing host cell invasion. Notably, the PTS mutant can prevent acute as well as yet-incurable chronic toxoplasmosis in a mouse model, which endorses its potential clinical utility as a metabolically attenuated vaccine. Together, the work also illustrates the functional speciation of two evolutionarily related membrane phospholipids, i.e., PtdThr and PtdSer.

PMID:

26565995

[PubMed - as supplied by publisher]

Induction of depression-related behaviors by reactivation of chronic Toxoplasma gondii infection in mice

Behav Brain Res. 2015 Nov 7. pii: S0166-4328(15)30276-X. doi: 10.1016/j.bbr.2015.11.005. [Epub ahead of print]

Mahmoud ME1, Ihara F2, Fereig RM2, Nishimura M2, Nishikawa Y3.

Author information

Abstract

Although Toxoplasma gondii (T. gondii) infection is relevant to many psychiatric disorders, the fundamental mechanisms of its neurobiological correlation with depression are poorly understood. Here, we show that reactivation of chronic infection by an immunosuppressive regimen caused induction of depressive-like behaviors without obvious sickness symptoms. However, the depression-related behaviors in T. gondii-infected mice, specifically, reduced sucrose preference and increased immobility in the forced-swim test were observed at the reactivation stage, but not in the chronic infection. Interestingly, reactivation of T. gondii was associated with production of interferon-gamma and activation of brain indoleamine 2, 3-dioxygenase, which converts tryptophan to kynurenine and makes it unavailable for serotonin synthesis. Furthermore, serotonin turnover to its major metabolite, 5-hydroxyindoleacetic acid, was also enhanced at the reactivation stage. Thus, enhanced tryptophan catabolic shunt and serotonin turnover may be implicated in development of depressive-like behaviors in mice with reactivated T. gondii.

Copyright © 2015. Published by Elsevier B.V.

KEYWORDS: 

3 dioxygenase; Depressive-like behaviors; Indoleamine 2; Reactivation; Toxoplasma gondii; mouse

PMID:

 

26554725

 

[PubMed - as supplied by publisher]

Toxoplasma gondii GRA7-induced TRAF6 activation contributes to host protective immunity

Infect Immun. 2015 Nov 9. pii: IAI.00734-15. [Epub ahead of print]

Yang CS1, Yuk JM2, Lee YH3, Jo EK3.

Author information

Abstract

The intracellular parasite Toxoplasma gondii (T. gondii) has unique dense granule antigens (GRAs) that are crucial for host infection. Emerging evidence suggests that the GRA7 of T. gondii is a promising serodiagnostic marker and an effective vaccine candidate against toxoplasmosis; however, little information is known about intracellular regulatory mechanisms involved in GRA7-induced host responses. Here we show that GRA7-induced MyD88 signaling through the activation of TRAF6 and production of reactive oxygen species (ROS) is required for the induction of NF-kB-mediated pro-inflammatory responses by macrophages. GRA7 stimulation resulted in the rapid activation of mitogen-activated protein kinases (MAPKs) and an early burst of ROS in macrophages in a MyD88-dependent manner. GRA7 induced a physical association between GRA7 and TRAF6 via MyD88. Remarkably, the C-terminal of GRA7 (GRA7-V) was sufficient for interaction and ubiquitination of RING domain of TRAF6, which is capable of inflammatory cytokine production. Interestingly, the generation of ROS and TRAF6 activation is mutually dependent on GRA7/MyD88-mediated signaling in macrophages. Furthermore, mice immunized with GRA7-V showed markedly increased Th1 immune responses and protective efficacy against T. gondii infection. Collectively, these results provide novel insight into the crucial role of GRA7-TRAF6 signaling in innate immune responses.

Copyright © 2015 Yang et al.

PMID:

 

26553469

 

[PubMed - as supplied by publisher] 

Zebra mussel as a new tool to show evidence of freshwater contamination by waterborne Toxoplasma gondii

J Appl Microbiol. 2015 Nov 9. doi: 10.1111/jam.12999. [Epub ahead of print]

 

Kerambrun E¹, Palos Ladeiro M^1,2, Bigot-Clivot A¹, Dedourge-Geffard O¹, Dupuis E², Villena I², Aubert D², Geffard A¹.

AIMS:

The objective of this study was to evaluate if freshwater bivalves can be used to detect the presence of Toxoplasma gondii in water bodies.

METHODS AND RESULTS:

Zebra mussels (Dreissena polymorpha) were caged for one month upstream and downstream of the discharge points of wastewater treatment plants (WWTPs). Physiological status was assessed to assure good health of bivalves during transplantation. The presence of T. gondii was investigated in mussel tissues by qPCR. In autumn, T. gondii was detected in mussels caged downstream of the discharge points of two WWTPs. In spring, it was detected upstream of one WWTP.

CONCLUSIONS:

For the first time, T. gondii DNA has been shown in a continental mollusc in environmental conditions. This highlights the interest of an active approach that could be applied independently of the presence or accessibility of autochthonous populations, and underlines the presence of T. gondii in natural waters under pressure of WWTP discharge at a certain time of the year.

SIGNIFICANCE AND IMPACT OF THE STUDY:

This study shows that transplanted zebra mussels could be used as biosamplers to reveal contamination of freshwater systems by T. gondii. This article is protected by copyright. All rights reserved.
This article is protected by copyright. All rights reserved.

KEYWORDS:

Dreissena polymorpha ; Toxoplasma gondii ; qPCR ; Rivers; Wastewater

PMID:

26551548

[PubMed - as supplied by publisher]

Phosphorylation of a Myosin Motor by TgCDPK3 Facilitates Rapid Initiation of Motility during Toxoplasma gondii egress

PLoS Pathog. 2015 Nov 6;11(11):e1005268. doi: 10.1371/journal.ppat.1005268. eCollection 2015.

Gaji RY1, Johnson DE2,3, Treeck M4, Wang M2, Hudmon A2,3, Arrizabalaga G1.

Author information

Abstract

Members of the family of calcium dependent protein kinases (CDPK's) are abundant in certain pathogenic parasites and absent in mammalian cells making them strong drug target candidates. In the obligate intracellular parasite Toxoplasma gondii TgCDPK3 is important for calcium dependent egress from the host cell. Nonetheless, the specific substrate through which TgCDPK3 exerts its function during egress remains unknown. To close this knowledge gap we applied the proximity-based protein interaction trap BioID and identified 13 proteins that are either near neighbors or direct interactors of TgCDPK3. Among these was Myosin A (TgMyoA), the unconventional motor protein greatly responsible for driving the gliding motility of this parasite, and whose phosphorylation at serine 21 by an unknown kinase was previously shown to be important for motility and egress. Through a non-biased peptide array approach we determined that TgCDPK3 can specifically phosphorylate serines 21 and 743 of TgMyoA in vitro. Complementation of the TgmyoA null mutant, which exhibits a delay in egress, with TgMyoA in which either S21 or S743 is mutated to alanine failed to rescue the egress defect. Similarly, phosphomimetic mutations in the motor protein overcome the need for TgCDPK3. Moreover, extracellular Tgcdpk3 mutant parasites have motility defects that are complemented by expression of S21+S743 phosphomimetic of TgMyoA. Thus, our studies establish that phosphorylation of TgMyoA by TgCDPK3 is responsible for initiation of motility and parasite egress from the host-cell and provides mechanistic insight into how this unique kinase regulates the lytic cycle of Toxoplasma gondii.

PMID:

 

26544049

 

[PubMed - as supplied by publisher]

Increased expressions of ADAMTS-13 and apoptosis contribute to neuropathology during Toxoplasma gondii encephalitis in mice

Neuropathology. 2015 Nov 6. doi: 10.1111/neup.12263. [Epub ahead of print]

Dincel GC1, Atmaca HT2.

Author information

Abstract

Toxoplasma gondii (T. gondii) is a protozoan parasite with the potential of causing severe encephalitis among immunocompromised humans and animals. Our previous study showed that T. gondii induces high nitric oxide (NO) production, high glial activation (GFAP) and neurofilament expressions, leading to severe neurodegeneration in toxoplasma encephalitis (TE) in the central nervous system (CNS). The aim of this experimental study was to investigate ADAMTS-13 expression and apoptosis in CNS and to identify whether they have any correlation with toxoplasmosis neuropathology and neurodegeneration. Mice were infected with ME49 strain T. gondii and the levels of ADAMTS-13, caspase 3, caspase 8, caspase 9, TNFR1 and Bcl-xL expressions were examined in brain tissues by immunohistochemistry, during the development and establishment of chronic infections at 10, 30 and 60 days post-infection. Results of the study revealed that the levels of ADAMTS-13 (P < 0.005), caspase 3 (P < 0.05), caspase 8 (P < 0.05), caspase 9 (P < 0.005) and TNFR1 (P < 0.05) expressions in the brain markedly increased while Bcl-xL expression decreased (P < 0.005). The most prominent finding from our study was that 10, 30 and 60 days post-infection ADAMTS-13 increased significantly and this may play an important role in the regulation and protection of the blood-brain barrier integrity and CNS microenvironment in TE. These results also suggest that T. gondii-mediated apoptosis might play a pivotal role and a different type of role in the mechanism of neurodegeneration and neuropathology in the process of TE. Furthermore, expression of ADAMTS-13 might give an idea of the progress and is critical for diagnosis of this disease. To the best of the authors' knowledge, this is the first report on ADAMTS-13 expression in the CNS of T. gondii-infected mice.

© 2015 Japanese Society of Neuropathology.

KEYWORDS: 

ADAMTS-13; Toxoplasma gondii; apoptosis; neurodegeneration; neuropathology

PMID:

 

26542631

 

[PubMed - as supplied by publisher]