scholarly journals Alkyl Hydroperoxide Reductase as a Determinant of Parasite Antiperoxide Response in Toxoplasma gondii

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Jinwen Wang ◽  
Qianqian Tan ◽  
Junpeng Chen ◽  
Xiaomei Liu ◽  
Zeyan Di ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Peroxidase Activity ◽  
Protozoan Parasite ◽  
Bioinformatic Analysis ◽  
Culture Conditions ◽  
Alkyl Hydroperoxide Reductase ◽  
Enzyme Active Site ◽  
Alkyl Hydroperoxide ◽  
Tert Butyl Hydroperoxide ◽  
Key Enzyme

Toxoplasma gondii is a protozoan parasite that is widely parasitic in the nucleated cells of warm-blooded animals. Bioinformatic analysis of alkyl hydroperoxide reductase 1 (AHP1) of T. gondii is a member of the Prxs family and exhibits peroxidase activity. Cys166 was certified to be a key enzyme active site of TgAHP1, indicating that the enzyme follows a cysteine-dependent redox process. TgAHP1 was present in a punctate staining pattern anterior to the T. gondii nucleus. Oxidative stress experiments showed that the ∆Ahp1 strain was more sensitive to tert-butyl hydroperoxide (tBOOH) than hydrogen peroxide (H2O2), indicating that tBOOH may be a sensitive substrate for TgAHP1. Under tBOOH culture conditions, the ∆Ahp1 strain was significantly less invasive, proliferative, and pathogenic in mice. This was mainly due to the induction of tBOOH, which increased the level of reactive oxygen species in the parasites and eventually led to apoptosis. This study shows that TgAHP1 is a peroxisomes protein with cysteine-dependent peroxidase activity and sensitive to tBOOH.

scholarly journals Isolating an active and inactive CACTA transposon from lettuce color mutants and characterizing their family

2021 ◽  
Author(s):  
Csanad Gurdon ◽  
Alexander Kozik ◽  
Rong Tao ◽  
Alexander Poulev ◽  
Isabel Armas ◽  
...  
Keyword(s):  
Anthocyanin Biosynthesis ◽  
Mobile Element ◽  
Bioinformatic Analysis ◽  
Relative Expression Level ◽  
Gene Coding ◽  
Genes Encoding ◽  
Key Enzyme ◽  
Natural Derivative ◽  
Dark Green ◽  
Transposon Insertions

Abstract Dietary flavonoids play an important role in human nutrition and health. Flavonoid biosynthesis genes have recently been identified in lettuce (Lactuca sativa); however, few mutants have been characterized. We now report the causative mutations in Green Super Lettuce (GSL), a natural light green mutant derived from red cultivar NAR; and GSL-Dark Green (GSL-DG), an olive-green natural derivative of GSL. GSL harbors CACTA 1 (LsC1), a 3.9-kb active nonautonomous CACTA superfamily transposon inserted in the 5′ untranslated region of anthocyanidin synthase (ANS), a gene coding for a key enzyme in anthocyanin biosynthesis. Both terminal inverted repeats (TIRs) of this transposon were intact, enabling somatic excision of the mobile element, which led to the restoration of ANS expression and the accumulation of red anthocyanins in sectors on otherwise green leaves. GSL-DG harbors CACTA 2 (LsC2), a 1.1-kb truncated copy of LsC1 that lacks one of the TIRs, rendering the transposon inactive. RNA-sequencing and reverse transcription quantitative PCR of NAR, GSL, and GSL-DG indicated the relative expression level of ANS was strongly influenced by the transposon insertions. Analysis of flavonoid content indicated leaf cyanidin levels correlated positively with ANS expression. Bioinformatic analysis of the cv Salinas lettuce reference genome led to the discovery and characterization of an LsC1 transposon family with a putative transposon copy number greater than 1,700. Homologs of tnpA and tnpD, the genes encoding two proteins necessary for activation of transposition of CACTA elements, were also identified in the lettuce genome.

scholarly journals Loss of the Conserved Alveolate Kinase MAPK2 Decouples Toxoplasma Cell Growth from Cell Division

mBio ◽  
2020 ◽  
Vol 11 (6) ◽  
Author(s):  
Xiaoyu Hu ◽  
William J. O’Shaughnessy ◽  
Tsebaot G. Beraki ◽  
Michael L. Reese
Keyword(s):  
Toxoplasma Gondii ◽  
Protein Kinases ◽  
Daughter Cell ◽  
Protozoan Parasite ◽  
Productive Infection ◽  
Centrosome Duplication ◽  
Loss Of Function ◽  
Content Type ◽  
Mitogen Activated Protein ◽  
Parasite Replication

ABSTRACT Mitogen-activated protein kinases (MAPKs) are a conserved family of protein kinases that regulate signal transduction, proliferation, and development throughout eukaryotes. The apicomplexan parasite Toxoplasma gondii expresses three MAPKs. Two of these, extracellular signal-regulated kinase 7 (ERK7) and MAPKL1, have been implicated in the regulation of conoid biogenesis and centrosome duplication, respectively. The third kinase, MAPK2, is specific to and conserved throughout the Alveolata, although its function is unknown. We used the auxin-inducible degron system to determine phenotypes associated with MAPK2 loss of function in Toxoplasma. We observed that parasites lacking MAPK2 failed to duplicate their centrosomes and therefore did not initiate daughter cell budding, which ultimately led to parasite death. MAPK2-deficient parasites initiated but did not complete DNA replication and arrested prior to mitosis. Surprisingly, the parasites continued to grow and replicate their Golgi apparatus, mitochondria, and apicoplasts. We found that the failure in centrosome duplication is distinct from the phenotype caused by the depletion of MAPKL1. As we did not observe MAPK2 localization at the centrosome at any point in the cell cycle, our data suggest that MAPK2 regulates a process at a distal site that is required for the completion of centrosome duplication and the initiation of parasite mitosis. IMPORTANCE Toxoplasma gondii is a ubiquitous intracellular protozoan parasite that can cause severe and fatal disease in immunocompromised patients and the developing fetus. Rapid parasite replication is critical for establishing a productive infection. Here, we demonstrate that a Toxoplasma protein kinase called MAPK2 is conserved throughout the Alveolata and essential for parasite replication. We found that parasites lacking MAPK2 protein were defective in the initiation of daughter cell budding and were rendered inviable. Specifically, T. gondii MAPK2 (TgMAPK2) appears to be required for centrosome replication at the basal end of the nucleus, and its loss causes arrest early in parasite division. MAPK2 is unique to the Alveolata and not found in metazoa and likely is a critical component of an essential parasite-specific signaling network.

scholarly journals Prevalence of Feline Immunodeficiency Virus and Toxoplasma gondii in Feral Cats on St. Kitts, West Indies

2021 ◽  
Vol 8 (2) ◽  
pp. 16
Author(s):  
Xinyu Chi ◽  
Kexin Fang ◽  
Liza Koster ◽  
Jevan Christie ◽  
Chaoqun Yao
Keyword(s):  
Toxoplasma Gondii ◽  
Feline Immunodeficiency Virus ◽  
Odds Ratio ◽  
Protozoan Parasite ◽  
Domestic Cat ◽  
Feral Cats ◽  
Immunodeficiency Virus ◽  
Polymerase Chain ◽  
One Year

Toxoplasma gondii (T. gondii) is a cosmopolitan protozoan parasite that infects all warm-blooded species including humans. The definitive hosts of T. gondii are felid vertebrates including the domestic cat. Domestic cats shed oocysts for approximately two weeks in their feces after the primary infection. It has been shown that feline immunodeficiency virus (FIV) positive cats have a higher prevalence of and a higher titer of antibodies to T. gondii than those of FIV-negative cats. The main purposes of this study were to determine FIV prevalence and to investigate the oocysts shedding in FIV-positive and FIV-negative feral cats on St. Kitts. Fecal samples were collected from feral cats while their FIV statues were determined using a commercial SNAP kit. Total fecal DNA of each cat was tested for the presence of T. gondii DNA using a polymerase chain reaction (PCR) consistently detecting one genome equivalent. A FIV-positive status was detected in 18 of 105 (17.1%, 95% confidence interval (CI): 9.9%−24.3%) feral cats sampled. Furthermore, males were three times more likely to be FIV positive than females (p = 0.017) with an odds ratio of 3.93 (95% CI: 1.20–12.89). Adults were found to have at least twice the prevalence of FIV compared to cats younger than one year of age (p = 0.056) with an odds ratio of 3.07 (95% CI: 0.94–10.00). Toxoplasma gondii DNA was not detected in the feces of any of the 18 FIV-positive (95% CI: 0%−0.18%) and 87 FIV-negative cats (95% CI: 0%−0.04%). A follow-up study with a much bigger sample size is needed to prove or disprove the hypothesis that FIV-positive cats have a higher prevalence of shedding T. gondii oocysts than FIV-negative cats.

Microtubules, but not actin filaments, drive daughter cell budding and cell division in Toxoplasma gondii

2000 ◽  
Vol 113 (7) ◽  
pp. 1241-1254 ◽  
Author(s):  
M.K. Shaw ◽  
H.L. Compton ◽  
D.S. Roos ◽  
L.G. Tilney
Keyword(s):  
Toxoplasma Gondii ◽  
Actin Cytoskeleton ◽  
Daughter Cell ◽  
Protozoan Parasite ◽  
Host Cells ◽  
Actin Dynamics ◽  
Residual Body ◽  
Cell Organelles ◽  
Infection Period ◽  
Parasite Replication

We have used drugs to examine the role(s) of the actin and microtubule cytoskeletons in the intracellular growth and replication of the intracellular protozoan parasite, Toxoplasma gondii. By using a 5 minute infection period and adding the drugs shortly after entry we can treat parasites at the start of intracellular development and 6–8 hours prior to the onset of daughter cell budding. Using this approach we found, somewhat surprisingly, that reagents that perturb the actin cytoskeleton in different ways (cytochalasin D, latrunculin A and jasplakinolide) had little effect on parasite replication although they had the expected effects on the host cells. These actin inhibitors did, however, disrupt the orderly turnover of the mother cell organelles leading to the formation of a large residual body at the posterior end of each pair of budding parasites. Treating established parasite cultures with the actin inhibitors blocked ionophore-induced egression of tachyzoites from the host cells, demonstrating that intracellular parasites were susceptible to the effects of these inhibitors. In contrast, the anti-microtubule drugs oryzalin and taxol, and to a much lesser extent nocodazole, which affect microtubule dynamics in different ways, blocked parasite replication by disrupting the normal assembly of the apical conoid and the microtubule inner membrane complex (IMC) in the budding daughter parasites. Centrosome replication and assembly of intranuclear spindles, however, occurred normally. Thus, daughter cell budding per se is dependent primarily on the parasite microtubule system and does not require a dynamic actin cytoskeleton, although disruption of actin dynamics causes problems in the turnover of parasite organelles.

scholarly journals Analysis of Structures and Epitopes of Surface Antigen Glycoproteins Expressed in Bradyzoites ofToxoplasma gondii

2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Hua Cong ◽  
Min Zhang ◽  
Qingli Zhang ◽  
Jing Gong ◽  
Haizi Cong ◽  
...  
Keyword(s):  
Immune Response ◽  
Toxoplasma Gondii ◽  
Immune Responses ◽  
Surface Antigen ◽  
Protein Sequence ◽  
Protozoan Parasite ◽  
3D Models ◽  
Chronic Infections ◽  
Homologous Proteins ◽  
Protein Sequence Alignment

Toxoplasma gondiiis a protozoan parasite capable of infecting humans and animals. Surface antigen glycoproteins, SAG2C, -2D, -2X, and -2Y, are expressed on the surface of bradyzoites. These antigens have been shown to protect bradyzoites against immune responses during chronic infections. We studied structures of SAG2C, -2D, -2X, and -2Y proteins using bioinformatics methods. The protein sequence alignment was performed by T-Coffee method. Secondary structural and functional domains were predicted using software PSIPRED v3.0 and SMART software, and 3D models of proteins were constructed and compared using the I-TASSER server, VMD, and SWISS-spdbv. Our results showed that SAG2C, -2D, -2X, and -2Y are highly homologous proteins. They share the same conserved peptides and HLA-I restricted epitopes. The similarity in structure and domains indicated putative common functions that might stimulate similar immune response in hosts. The conserved peptides and HLA-restricted epitopes could provide important insights on vaccine study and the diagnosis of this disease.

scholarly journals In silicoidentification of putativeTrypanosoma cruzienolase inhibitors

2019 ◽  
Author(s):  
Edward A. Valera-Vera ◽  
Melisa Sayé ◽  
Chantal Reigada ◽  
Mariana R. Miranda ◽  
Claudio A. Pereira
Keyword(s):  
Molecular Dynamics ◽  
Molecular Docking ◽  
Virtual Screening ◽  
Active Site ◽  
Screening Strategy ◽  
Glycolytic Enzyme ◽  
Docking Simulations ◽  
Enzyme Active Site ◽  
Key Enzyme

AbstractEnolase is a glycolytic enzyme that catalyzes the interconversion between 2-phosphoglycerate and phosphoenolpyruvate. In trypanosomatids enolase was proposed as a key enzyme afterin silicoandin vivoanalysis and it was validated as a protein essential for the survival of the parasite. Therefore, enolase constitutes an interesting enzyme target for the identification of drugs against Chagas disease. In this work, a combined virtual screening strategy was implemented, employing similarity virtual screening, molecular docking and molecular dynamics. First, two known enolase inhibitors and the enzyme substrates were used as queries for the similarity screening on the Sweetlead database using five different algorithms. Compounds retrieved in the top 10 of at least three search algorithms were selected for further analysis, resulting in six compounds of medical use (etidronate, pamidronate, fosfomycin, acetohydroximate, triclofos, and aminohydroxybutyrate). Molecular docking simulations predicted acetohydroxamate and triclofos would not bind to the active site of the enzyme, and a re-scoring of the obtained poses signaled fosfomycin and aminohydroxybutyrate as bad enzyme binders. Docking poses obtained for etidronate, pamidronate, and PEP, were used for molecular dynamics calculations to describe their mode of binding. From the obtained results, we propose etidronate as a possibleTcENO inhibitor, and describe desirable and undesirable molecular motifs to be taken into account in the repurposing or design of drugs aiming this enzyme active site.

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