• Korean Journal of Veterinary Research
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• v.13 no.1
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• pp.67-73
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• 1973

Toxoplasma gondii (Tp), RH strain, was inoculated into cultured buffy coat cells obtained from the swine blood. The main reason for adopting swine lies in the animal's unusual susceptibility to Tp, As for the culture method used in the experiment, those well proved methods practised by Cho, Merchant, Moore and Tarnvik were mainly referred to as a starting point: hence, the author's method has been turned out to be the modified or supplementary form of those methods. Observations were made on the phase of multiplication of Tp in the cytoplasm. The results obtained were as follows: 1. Better growth and multiplication of Toxoplasma gondii were noticeably observed in the swine buffy coat cell, inoculated after three-to-five day cultivation of the cell. 2. In the lapse of the observation period, there appeard Toxoplasma gondii rarely available in the earlier stage, which had been inoculated into the cell after three-to-five day cultivation. In other words, Toxoplasma gondii started to show itself in seven or eight hours after inoculation, most outstandingly noticeable between twenty four hours and forty eight hours. Thereafter the disintegration stage of Toxoplasma gondii was observed.

• Parasites, Hosts and Diseases
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• v.32 no.1
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• pp.19-26
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• 1994

An in uipo culturing to examine the cyst stage of ToxopLQsma gondii (ME49 strain) was Investigated using murine peritoneal macrophages, and we also examined the effect of CAMP or DHFR Inhibitors on the growth of bradyzoltes. For experiments ICR mice were Injected 1.p. with 1,500 brain cysts. At 1, 3, 5 and 7 days, peritoneal exudates were Isolated and then adherent peritoneal macrophages were cultured for 1,3,5 and 10 days. Growth pattern of bradyzoltes was measured by (3H)-uracil uptake assay and morphological pattern of pseudocysts formed in macrophages was observed Uth Glemsa stain. Mostly bradyzoites were observed In the macrophages extracted at 3 and S days post Infection. After 3 days in vitro, a number of pseudocysts were formed in the macrophages and the size of pseudocysts was increased during further 5 and 10 days in vitro culture. CAMP stimulated the growth of bradyzoltes when in uiuo 3 and 5 days and then in vitro 5 and 10 days conditions were applied. In case of.DHFR Inhibitors, pynmethamlne produced a linearly decremental effect with a cont.-dependent mode but methotrexate was not effective against Intracellular bradyzoltes or pseudocysts In this system. It was suggested that cyst-forming strain of T gondii (ME49 strain) could be maintained and cultivated in uitro by use of murine peritoneal macrophages. In uivo 3 and 5 days and then in uiko 5 and 10 days conditions appeared to be suitable for culturing of bradyzoltes. CAMP and pyrimethamine had an effect of stimulation and inhibition on the growth of bradyzolte, respectively.

• Parasites, Hosts and Diseases
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• v.28 no.4
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• pp.197-206
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• 1990

Various conditions of cultures were performed to investigate the role of tight junctions formed between adjacent MDCK cells on the entry of Toxoplasma. When MDCK cells were cocultured with excess number of Toxoplasma at the seeding density of 1×105, 3×105, and 5×105 cells/ml for 4 days, the number of intracellular parasites decreased rapidly as the host cells reached saturation density, i.e., the formation of tight junctions. When the concentration of calcium in the media (1.8 mM in general) was shifted to $5{\mu}M$ that resulted in the elimination of tight junction, the penetration of Toxoplasma increased about 2-fold(p<0.05) in the saturated culture, while that of non-saturated culture decreased by half. Trypsin-EDTA which was treated to conquer the tight junctions of saturated culture favored the entry of Toxoplasma about 2.5-fold(P<0.05) compared to the non-treated, while that of non- saturated culture decreased to about one fifth. It was suggested that the tight junctions of epithelial cells play a role as a barrier for the entry of Toxoplasma and Toxoplasma penetrate into hoot cells through membrane structure-specific, i.e., certain kind of receptors present on the basolateral rather than apical surface of MDCK cells.