Eimeria tenella: Stimulation of DNA synthesis in infected cultured animal cells

Invasion of chicken caecal and intestinal lamina propria by crypt epithelial cells infected with coccidia

“…Changes reported to occur in host cells during the development of the schizonts include enlargement of the cell and its nucleus, increase in nuclear DNA and RNA and induction of gel-phase lipid in the plasma membrane (Fernando, Pasternak, Barrell & Stockdale, 1974;Beyer & Shibalova, 1974;Fernando & Pasternak, 1977a, b;Thompson, Fernando & Pasternak, 1979). Similar changes in DNA synthesis are also evident in infected cultured cells (Browning, Patton & Lytle, 1976;Latter, 1977;Urquhart, 1981a) and have been shown to be transmissible to unparasitized cells (Urquhart, 1981a).…”

Thymidine uptake by chicken kidney cells parasitized by Eimeria tenella: evidence for a diffusable mediating substance

“…A stimulation of the host cell nuclei to incorporate [ 3 H]thymidine following parasitization has previously been described in vivo (Fernando,Pasternak,[ 3 H]Thymidine uptake in E. tenella-m/ec«ea! CK cells 193 Barrell & Stockdale, 1974;Fernando & Pasternak, 1977;Beyer & Shibalova, 1974) and in vitro (Browning et al 1976;Latter, 1977). The increase in DNA synthesis, although associated with nuclear hypertrophy, is unaccompanied by cell division (Beyer & Shibalova, 1974;Fernando et al 1974).…”

“…Previous reports of the in vitro stimulation of [ 3 H]thymidine uptake were those of Browning et al (1976) who described the effect of E. tenella on the incorporation of [ 3 H]thymidine by MDBK cells, and of Latter (1977) who described the effect of developing and differentiating second-generation schizonts of E. tenella on [ 3 H]thymidine incorporation by chick embryonic liver (CEL) cells. Browning et al (1976) mentioned that all cells in a parasitized culture were stimulated to take up thymidine regardless of whether they were parasitized or not, and attributed this to a diffusible substance. This was confirmed in the present work by the demonstration that the stimulus for enhanced [ 3 H]thymidine uptake could be transmitted via the medium to non-parasitized cells in co-culture.…”

“…It is possible that other known effects of the parasite on its host cell can be attributed to a similar transmissible factor. Browning, Patton & Lytle (1976) reported an increase in [ 3 H]thymidine uptake by cultured bovine kidney (MDBK) cells when parasitized by E. tenella and suggested that the high level of incorporation by both parasitized and non-parasitized cells in the parasitized cultures might have been due to a diffusible substance released into the medium by the parasite or the parasitized cell. The following report provides evidence for such a factor and also suggests the pattern or course of events which leads up to the alteration of the host cell's DNA synthetic processes.…”

Nucleolar Hypertrophy as an Indicator of Transcription in Cells Infected with Second Generation Meronts of Eimeria tenella1

“…AC- infected with Klossia hekina resulted from an increase in the amount of DNA, representing an attempt by the cell to maintain the nucleo-cytoplasmic ratio; in his view the host cell perceived the parasite as additional cytoplasm. In other studies, the change in the amount of DNA in infected cells was measured by Feulgen staining and microspectrophotometry (6,25) in vivo or by the uptake of 3H-thymidine in cell culture (1,7,30). The studies cited above have focused on changes in the DNA content of infected cells except for that of Fernando & Pasternak (7), in which both DNA and RNA were measured.…”