We have characterized the Toxoplasma gondii protein phosphatase type 1 (TgPP1) and a potential regulatory binding protein belonging to the leucine-rich repeat protein family, designated TgLRR1. TgLRR1 is capable of binding to TgPP1 to inhibit its activity and to override a G(2)/M cell cycle checkpoint in Xenopus oocytes. In the parasite, TgLRR1 mRNA and protein are both highly expressed in the ...

Past studies have stated that the parasitostatic effect of IFN-γ is most likely due to the starvation of Toxoplasma gondii for tryptophan in the host cell. The aim of this study was to evaluate the direct effect of two new Naphthalene-Sulfonyl-Indole compounds as competitive molecules for tryptophan on viability and infectivity of Toxoplasma tachyzoites. Tachyzoites of RH strain were incubated ...

background: the aim of this study was to evaluate the effects of conjugated lino-leic acid (cla) on apoptosis of tachyzoites of t . gondii , rh strain (type i) and the cyst-forming tehran strain (type ii) in vitro. methods: toxoplasma strains were injected into the peritoneal cavity of balb/c mice. the tehran strain forms cysts in the brain of mice. bradyzoites within the cysts are reactivated ...

Toxoplasma gondii Korean isolate (KI-1) tachyzoites were inoculated intraduodenally to BALB/c mice using a silicon tube, and the course of infection and immune responses of mice were studied. Whereas control mice, that were infected intraperitoneally, died within day 7 post-infection (PI), the intraduodenally infected mice survived until day 9 PI (infection with 1 × 10(5) tachyzoites) or day 11...

Toxoplasma gondii was first identified more than 100 years ago in the tissues of birds and mammals. In 1908 Nicolle and Manceoux described it for the first time in the gundi (Ctenodactylus gundi), a North African rodent, in tachyzoite forms. At the same time, Splendore in Brazil, identified the parasite in rabbit tissues. Due to its bow-like shape (Greek: Toxo = Arc) the genus was named Toxopla...

The addition of PP(i) promoted the acidification of a subcellular compartment in cell homogenates of Toxoplasma gondii tachyzoites, implying the presence of a proton-translocating pyrophosphatase. The proton gradient was collapsed by addition of the K(+)/H(+) antiporter nigericin, and was also inhibited by addition of the PP(i) analogue aminomethylenediphosphonate (AMDP). Both proton transport ...

Natural killer (NK) cells are considered to be key players in the early innate responses to protozoan infections, primarily indirectly by producing gamma interferon (IFN-gamma) in response to cytokines, like interleukin 12 (IL-12). We demonstrate that live, as well as heat-inactivated, tachyzoites of Neospora caninum, a Toxoplasma-like protozoan, directly trigger production of IFN-gamma from pu...

The tachyzoite stage of the protozoan parasite Toxoplasma gondii has two populations of microtubules: spindle microtubules and subpellicular microtubules. To determine how these two microtubule populations are regulated, we investigated microtubule behavior during the cell cycle following treatment with microtubule-disrupting drugs. Previous work had established that the microtubule populations...

Oral-route infection with Toxoplasma gondii sporozoites or tachyzoites leads to the rapid spread of quick-replicating cytolytic tachyzoites throughout the whole body. Toxoplasma easily crosses the blood-retina, encephalic and placental barriers. The acute phase of this infection lasts for less than around ten days. The parasite causes a very strong type-1 response focused on the interferon-gamm...