Because the obligate intracellular parasite Toxoplasma gondii lacks the ability to synthesize cholesterol, T. gondii needs to obtain cholesterol from host cells. Am80 is known to reduce the cellular cholesterol and lipid bodies in macrophages. In this study, we demonstrated that inhibition of acquisition and synthesis of cholesterol in macrophage cell line J774A.1 by a synthetic retinoid Am80 suppressed the growth of T. gondii. Am80 inhibited T. gondii-induced high levels of cellular cholesterol in J774A.1 cells while the level of cellular TAG was increased by treatment with the drug. Furthermore, the expression of LDLR was down regulated in the Am80-treated cells. Am80 reduced the expression of HMG-CoA reductase and ACAT1, and increased DGAT1 expression. These results suggest that cholesterol acquisition via LDLR and cholesterol synthesis is necessary for T. gondii growth though the roles of cellular TAG are still unknown. Finally, we studied the effect of Am80 in vivo. Mice treated with 1.0 mg/kg of Am80 ameliorated acute toxoplasmosis. Our findings support the notion that modulation of the lipid metabolism in host cells is a potential strategy for the treatment and prevention of toxoplasmosis.

抄録全体を表示

In the present study the seroprevalence of Babesia caballi and Theileria equi, the causative agents for equine piroplasmosis was investigated in Northern Thailand through a cross sectional survey carried out in December 2011. Two hundred forty equids sera from a complex of farms located in Chiang Mai Province were examined by enzyme-linked immunosorbent assay (ELISA), indirect fluorescent antibody test (IFAT) and polymerase chain reaction (PCR). Overall seroprevalence of T. equi by ELISA and IFAT was 5.42% (13/240) and 8.75% (21/240) while that of B. caballi was 2.50% (6/240) and 5.00% (12/240), respectively. Molecular assay found T. equi infection in 3 mules (1.25%) while none of B. caballi was detected. The IFAT results showed that prevalence of T. equi was significantly higher in mules (10.73%) than in horses (3.17%), whereas prevalence of B. caballi was higher in horses (11.11%) than in mules (2.82%). Risk factor analysis based on IFAT results showed that occupation related to the host breed was significantly associated to equine piroplasmosis seropositivity (p < 0.05). Present results provide important information regarding the prevalence of equine piroplasmosis in horses and mules in the Northern region of Thailand, which should be beneficial for better prevention and control of this disease.

抄録全体を表示

Aspartic proteases are proposed as attractive drug targets of pathogens including apicomplexan parasites. In the present study, a gene encoding aspartic protease 3 of Toxoplasma gondii (TgASP3) was cloned, expressed and characterized. The gene fragment of putative functional domain of TgASP3 was expressed in Escherichia coli as a recombinant glutathione-S-transferase (GST) fusion protein (rTgASP3d). The native TgASP3 with molecular mass of 66-kDa from T. gondii tachyzoites was identified by Western blot analysis using anti-rTgASP3d mouse serum. In addition, the result from immunofluorescent antibody test (IFAT) using anti-rTgASP3d suggests that the native TgSAP3 is localized in the cytoplasm of T. gondii tachyzoites. On the other hand, the growth of T. gondii tachyzoites was significantly inhibited by an aspartic protease inhibitor-pepstatin A. These results suggest that the TgASP3 might be a novel therapeutic target for T. gondii infection.

抄録全体を表示

This paper intends to report abortion in gilts and its probable cause in an experimental infection with T. brucei. Twelve domestic crossbred female piglets aged eight weeks and two boars aged eight months were purchased from piggeries in Samaru Zaria, Nigeria and housed in clean fly proof pens. When the piglets attained puberty, they were divided into two groups, six experimental and six uninfected control. During their third estrus period, all the gilts were bred randomly by the two boars whose fertility had been previously determined. When the gilts were between 35 and 39 days pregnant, the ones in the experimental group were inoculated each with two milliliters of the infected blood containing 1.8×10⁶ parasites via the anterior vena cava. The gilts in the control group were not inoculated. All the inoculated pigs developed clinical trypanosomosis characterized by fever, pale mucous membranes, anorexia, dullness, reduction in feed intake, reduced weight gain, weight loss, emaciation, short and moist cough, moist rales, mucopurulent ocular discharges, hyperemia of the skin, lethargy, un-coordinated movements, posterior paresis, recumbency and death of two infected gilts. The gilts in the control group carried their pregnancies to term and farrowed normally but those in the experimental group had their pregnancies terminated between 40 and 58 days post breeding. The probable cause of loss of pregnancy of these gilts was pyrexia

抄録全体を表示