scholarly journals Lytic Cycle of Toxoplasma gondii

2000 ◽  
Vol 64 (3) ◽  
pp. 607-623 ◽  
Author(s):  
Michael W. Black ◽  
John C. Boothroyd
Keyword(s):  
Toxoplasma Gondii ◽  
Current Knowledge ◽  
Protozoan Parasite ◽  
Geographic Range ◽  
Lytic Cycle ◽  
Broad Host Range ◽  
Intracellular Pathogen ◽  
Obligate Intracellular ◽  
Obligate Intracellular Pathogen ◽  
Serious Disease

SUMMARY Toxoplasma gondii is an obligate intracellular pathogen within the phylum Apicomplexa. This protozoan parasite is one of the most widespread, with a broad host range including many birds and mammals and a geographic range that is nearly worldwide. While infection of healthy adults is usually relatively mild, serious disease can result in utero or when the host is immunocompromised. This sophisticated eukaryote has many specialized features that make it well suited to its intracellular lifestyle. In this review, we describe the current knowledge of how the asexual tachyzoite stage of Toxoplasma attaches to, invades, replicates in, and exits the host cell. Since this process is closely analogous to the way in which viruses reproduce, we refer to it as the Toxoplasma “lytic cycle.”

scholarly journals Host-derived glucose and its transporter in the obligate intracellular pathogen Toxoplasma gondii are dispensable by glutaminolysis

2009 ◽  
Vol 106 (31) ◽  
pp. 12998-13003 ◽  
Author(s):  
M. Blume ◽  
D. Rodriguez-Contreras ◽  
S. Landfear ◽  
T. Fleige ◽  
D. Soldati-Favre ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Intracellular Pathogen ◽  
Obligate Intracellular ◽  
Obligate Intracellular Pathogen

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.

scholarly journals Hydroxylamine and Carboxymethoxylamine Can Inhibit Toxoplasma gondii Growth through an Aspartate Aminotransferase-Independent Pathway

2020 ◽  
Vol 64 (3) ◽  
Author(s):  
Jixu Li ◽  
Huanping Guo ◽  
Eloiza May Galon ◽  
Yang Gao ◽  
Seung-Hun Lee ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Drug Targets ◽  
Protozoan Parasite ◽  
Cell Types ◽  
Lytic Cycle ◽  
Type I ◽  
Content Type ◽  
Mechanism Of Inhibition

ABSTRACT Toxoplasma gondii is an obligate intracellular protozoan parasite and a successful parasitic pathogen in diverse organisms and host cell types. Hydroxylamine (HYD) and carboxymethoxylamine (CAR) have been reported as inhibitors of aspartate aminotransferases (AATs) and interfere with the proliferation in Plasmodium falciparum. Therefore, AATs are suggested as drug targets against Plasmodium. The T. gondii genome encodes only one predicted AAT in both T. gondii type I strain RH and type II strain PLK. However, the effects of HYD and CAR, as well as their relationship with AAT, on T. gondii remain unclear. In this study, we found that HYD and CAR impaired the lytic cycle of T. gondii in vitro, including the inhibition of invasion or reinvasion, intracellular replication, and egress. Importantly, HYD and CAR could control acute toxoplasmosis in vivo. Further studies showed that HYD and CAR could inhibit the transamination activity of rTgAAT in vitro. However, our results confirmed that deficiency of AAT in both RH and PLK did not reduce the virulence in mice, although the growth ability of the parasites was affected in vitro. HYD and CAR could still inhibit the growth of AAT-deficient parasites. These findings indicated that HYD and CAR inhibition of T. gondii growth and control of toxoplasmosis can occur in an AAT-independent pathway. Overall, further studies focusing on the elucidation of the mechanism of inhibition are warranted. Our study hints at new substrates of HYD and CAR as potential drug targets to inhibit T. gondii growth.

Cell death and inflammation during infection with the obligate intracellular pathogen, Chlamydia

Biochimie ◽  
2003 ◽  
Vol 85 (8) ◽  
pp. 763-769 ◽  
Author(s):  
Jean-Luc Perfettini ◽  
Véronique Hospital ◽  
Lynn Stahl ◽  
Thomas Jungas ◽  
Philippe Verbeke ◽  
...  
Keyword(s):  
Cell Death ◽  
Intracellular Pathogen ◽  
Obligate Intracellular ◽  
Obligate Intracellular Pathogen

scholarly journals Investigation of Toxoplasma gondii Infection in Aborted Fetuses of Sheep Using PCR: A Study in North Khorasan Province, Iran

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Mitra Salehi ◽  
Hosein Nezami ◽  
Hamid Reza Niazkar
Keyword(s):  
Toxoplasma Gondii ◽  
Gestational Age ◽  
Protozoan Parasite ◽  
Abortion Rate ◽  
Obligate Intracellular ◽  
Significant Difference ◽  
Pcr Method ◽  
Toxoplasma Gondii Infection ◽  
Intracellular Protozoan Parasite

Toxoplasma gondii is a zoonotic obligate intracellular protozoan parasite that infects warm-blooded animals as well as humans worldwide. The purpose of this study was to delineate the prevalence of Toxoplasma infection in aborted fetuses of sheep in North Khorasan province, Iran. Three hundred and ninety-nine samples of the liver (133 samples), placenta (133 samples), and brain (133 samples) from 133 aborted fetuses of sheep were collected from 2015 to 2017. The ages of aborted fetuses were higher than 120 days’ gestational age in this study. According to the samples, sixteen out of 133 aborted fetuses of sheep were infected with T. gondii. Toxoplasma DNA was found in the placenta (68.75%) and liver (31.25%) samples of infected fetuses using the PCR method. The highest and lowest rates of Toxoplasma infection were observed during 2016 and 2017, respectively. Shirvan and Faruj provinces were recognized as the two most infected districts among others. There was a significant difference between the year and abortion rate in sheep due to infection by the Toxoplasma parasite (P<0.05). Furthermore, no significant difference between the prevalence of T. gondii infection and aborted fetuses was seen (P>0.05) in different areas. According to the present study, T. gondii infection can be one of the causes of fetus abortion of sheep in North Khorasan province, Iran.

scholarly journals Hijacking and Use of Host Kinases by Chlamydiae

Pathogens ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 1034
Author(s):  
Prakash Sah ◽  
Erika I. Lutter
Keyword(s):  
Host Cell ◽  
Intracellular Pathogen ◽  
Host Proteins ◽  
Sexually Transmitted ◽  
Obligate Intracellular ◽  
Host Cell Apoptosis ◽  
Survival And Development ◽  
Causative Agents ◽  
Cell Processes ◽  
Obligate Intracellular Pathogen

Chlamydia species are causative agents of sexually transmitted infections, blinding trachoma, and animal infections with zoonotic potential. Being an obligate intracellular pathogen, Chlamydia relies on the host cell for its survival and development, subverting various host cell processes throughout the infection cycle. A key subset of host proteins utilized by Chlamydia include an assortment of host kinase signaling networks which are vital for many chlamydial processes including entry, nutrient acquisition, and suppression of host cell apoptosis. In this review, we summarize the recent advancements in our understanding of host kinase subversion by Chlamydia.

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