scholarly journals A selector of transcription initiation in the protozoan parasite Toxoplasma gondii.

1995 ◽  
Vol 15 (1) ◽  
pp. 87-93 ◽  
Author(s):  
D Soldati ◽  
J C Boothroyd
Keyword(s):  
Toxoplasma Gondii ◽  
Gene Transcription ◽  
Transcription Initiation ◽  
Protozoan Parasite ◽  
Intracellular Parasite ◽  
Transcription Start ◽  
Transcription Start Sites ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite ◽  
Sag1 Gene

The recent development of an efficient transfection system for the apicomplexan Toxoplasma gondii allows a comprehensive dissection of the elements involved in gene transcription in this obligate intracellular parasite. We demonstrate here that for the SAG1 gene, a stretch of six repeated sequences in the region 35 to 190 bp upstream of the first of two transcription start sites is essential for efficient and accurate transcription initiation. This repeat element shows characteristics of a selector in determining the position of the transcription start sites.

The occurrence of Toxoplasma gondii on raw leafy vegetables in Gaza - Palestine

2020 ◽  
Author(s):  
Zuhair Dardona ◽  
Samia BOUSSAA ◽  
Adnan Al-Hindi ◽  
Ali aboumezzough ◽  
Mohamed Hafidi
Keyword(s):  
Toxoplasma Gondii ◽  
Solution Method ◽  
Leafy Vegetables ◽  
Foodborne Diseases ◽  
Intracellular Parasite ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite ◽  
Flotation Technique ◽  
Pcr Method ◽  
The Relationship

Toxoplasma gondii  a ubiquitous obligate intracellular parasite that can infect all warm-blooded animals, is one of the main pathogens causing foodborne diseases worldwide. In Gaza – Palestine, the leafy vegetables are frequently eaten raw.  The present study was carried out to investigate the occurrence of T. gondii oocyst in local leafy vegetables. For this purpose, fifty samples of each kind of six different leafy plants sold in markets, supermarkets, and retail sellers were randomly collected during the period from March to August 2019. , the three hundred samples were collected from six different species of leafy vegetables. The samples were examined microscopy through using a light microscope and after performing the flotation technique of Sheather's solution to easily detect the oocysts, the suspected samples were confirmed by using PCR technique. Upon analyzing the samples and using the PCR method, only 19 out of the 300 samples (6.33 %) were found to be contaminated, whereas by using Sheather's solution method, 35 out of the 300 samples (11.66%) were contaminated. Among the six various plants and according to the PCR method, mint held the highest rate of contamination (10.00 %), followed by both watercress and dill with a similar percentage (8.00%), parsley (6.00%), thyme (4.00%),  and finally, lettuce carrying the lowest rate (2.00%). Even though the sequence among those contaminated plants was found similar in the PCR and the Sheather's solution, the rates were different. With this method, mint stood at (18.00%), watercress (14.00%), dill (13.00%), parsley (10.00%), thyme (10.00%) and lettuce (6.00%). Moreover, the present study has reported that the relationship between the period of collection and T. gondii contamination is statistically significant. Whereby, the highest rate of contamination recorded was in July, followed by June, then August. Based on the findings of the present study, leafy vegetables are quite vulnerable to T. gondii contamination.

Documented Outbreaks of Toxoplasmosis: Transmission of Toxoplasma gondii to Humans

1993 ◽  
Vol 56 (7) ◽  
pp. 630-639 ◽  
Author(s):  
JAMES L. SMITH
Keyword(s):  
Toxoplasma Gondii ◽  
Food Supply ◽  
Control Mechanisms ◽  
Intracellular Parasite ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite ◽  
Toxoplasma Gondii Infection ◽  
The U.S

Toxoplasmosis, a disease of mammals and birds, is caused by the obligate intracellular parasite, Toxoplasma gondii. Infection by the parasite is common (35–50% of the U.S. population are infected), but the disease, toxoplasmosis, is relatively rare and outbreaks of the disease are seldom seen. Documented outbreaks of toxoplasmosis are discussed to illustrate conditions that lead to outbreaks and how T. gondii is transmitted to humans. Recommendations are made of means to prevent introduction of the parasite into the environment and food supply as well as control mechanisms to prevent infection in humans and animals.

scholarly journals Making Home Sweet and Sturdy: Toxoplasma gondii ppGalNAc-Ts Glycosylate in Hierarchical Order and Confer Cyst Wall Rigidity

mBio ◽  
2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Tadakimi Tomita ◽  
Tatsuki Sugi ◽  
Rama Yakubu ◽  
Vincent Tu ◽  
Yanfen Ma ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Cyst Wall ◽  
Dependent Manner ◽  
Intracellular Parasite ◽  
Congenital Disease ◽  
Brain Cyst ◽  
Obligate Intracellular ◽  
Obligate Intracellular Parasite ◽  
Structural Rigidity ◽  
The Brain

ABSTRACT The protozoan intracellular parasite Toxoplasma gondii forms latent cysts in the central nervous system (CNS) and persists for the lifetime of the host. This cyst is cloaked with a glycosylated structure called the cyst wall. Previously, we demonstrated that a mucin-like glycoprotein, CST1, localizes to the cyst wall and confers structural rigidity on brain cysts in a mucin-like domain-dependent manner. The mucin-like domain of CST1 is composed of 20 units of threonine-rich tandem repeats that are O-GalNAc glycosylated. A family of enzymes termed polypeptide N-acetylgalactosaminyltransferases (ppGalNAc-Ts) initiates O-GalNAc glycosylation. To identify which isoforms of ppGalNAc-Ts are responsible for the glycosylation of the CST1 mucin-like domain and to evaluate the function of each ppGalNAc-T in the overall glycosylation of the cyst wall, all five ppGalNAc-T isoforms were deleted individually from the T. gondii genome. The ppGalNAc-T2 and -T3 deletion mutants produced various glycosylation defects on the cyst wall, implying that many cyst wall glycoproteins are glycosylated by T2 and T3. Both T2 and T3 glycosylate the CST1 mucin-like domain, and this glycosylation is necessary for CST1 to confer structural rigidity on the cyst wall. We established that T2 is required for the initial glycosylation of the mucin-like domain and that T3 is responsible for the sequential glycosylation on neighboring acceptor sites, demonstrating hierarchical glycosylation by two distinct initiating and filling-in ppGalNAc-Ts in an intact organism. IMPORTANCE Toxoplasma gondii is an obligate intracellular parasite that infects a third of the world’s population. It can cause severe congenital disease and devastating encephalitis in immunocompromised individuals. We identified two glycosyltransferases, ppGalNAc-T2 and -T3, which are responsible for glycosylating cyst wall proteins in a hierarchical fashion. This glycosylation confers structural rigidity on the brain cyst. Our studies provide new insights into the mechanisms of O-GalNAc glycosylation in T. gondii. IMPORTANCE Toxoplasma gondii is an obligate intracellular parasite that infects a third of the world’s population. It can cause severe congenital disease and devastating encephalitis in immunocompromised individuals. We identified two glycosyltransferases, ppGalNAc-T2 and -T3, which are responsible for glycosylating cyst wall proteins in a hierarchical fashion. This glycosylation confers structural rigidity on the brain cyst. Our studies provide new insights into the mechanisms of O-GalNAc glycosylation in T. gondii.

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